Merge #2801

2801: chore(deps): bump tokio from 1.5.0 to 1.8.0 r=quake,yangby-cryptape,driftluo a=dependabot[bot]

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.5.0 to 1.8.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/tokio-rs/tokio/releases">tokio's releases</a>.</em></p>
<blockquote>
<h2>tokio-1.8.0</h2>
<h1>1.8.0 (July 2, 2021)</h1>
<h3>Added</h3>
<ul>
<li>io: add <code>get_{ref,mut}</code> methods to <code>AsyncFdReadyGuard</code> and <code>AsyncFdReadyMutGuard</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3807">#3807</a>)</li>
<li>io: efficient implementation of vectored writes for <code>BufWriter</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3163">#3163</a>)</li>
<li>net: add ready/try methods to <code>NamedPipe{Client,Server}</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3866">#3866</a>, <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3899">#3899</a>)</li>
<li>sync: add <code>watch::Receiver::borrow_and_update</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3813">#3813</a>)</li>
<li>sync: implement <code>From&lt;T&gt;</code> for <code>OnceCell&lt;T&gt;</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3877">#3877</a>)</li>
<li>time: allow users to specify Interval behaviour when delayed (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3721">#3721</a>)</li>
</ul>
<h3>Added (unstable)</h3>
<ul>
<li>rt: add <code>tokio::task::Builder</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3881">#3881</a>)</li>
</ul>
<h3>Fixed</h3>
<ul>
<li>net: handle HUP event with <code>UnixStream</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3898">#3898</a>)</li>
</ul>
<h3>Documented</h3>
<ul>
<li>doc: document cancellation safety (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3900">#3900</a>)</li>
<li>time: add wait alias to sleep (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3897">#3897</a>)</li>
<li>time: document auto-advancing behaviour of runtime (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3763">#3763</a>)</li>
</ul>
<p><a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3163">#3163</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3163">tokio-rs/tokio#3163</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3721">#3721</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3721">tokio-rs/tokio#3721</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3763">#3763</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3763">tokio-rs/tokio#3763</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3807">#3807</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3807">tokio-rs/tokio#3807</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3813">#3813</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3813">tokio-rs/tokio#3813</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3866">#3866</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3866">tokio-rs/tokio#3866</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3877">#3877</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3877">tokio-rs/tokio#3877</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3881">#3881</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3881">tokio-rs/tokio#3881</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3897">#3897</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3897">tokio-rs/tokio#3897</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3898">#3898</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3898">tokio-rs/tokio#3898</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3899">#3899</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3899">tokio-rs/tokio#3899</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3900">#3900</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3900">tokio-rs/tokio#3900</a></p>
<h2>Tokio v1.7.1</h2>
<h3>Fixed</h3>
<ul>
<li>runtime: fix early task shutdown during runtime shutdown (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3870">#3870</a>)</li>
</ul>
<p><a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3870">#3870</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3870">tokio-rs/tokio#3870</a></p>
<h2>Tokio v1.7.0</h2>
<h1>1.7.0 (June 15, 2021)</h1>
<h3>Added</h3>
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</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/tokio-rs/tokio/commit/677107d8d9278265798c5efdc75374a25b41a4b8"><code>677107d</code></a> chore: prepare Tokio v1.8.0 (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3912">#3912</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/c8ecfc894d06db466fe14b90f8b7f64eb3a3d5ea"><code>c8ecfc8</code></a> sync: fix watch borrow_and_update (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3913">#3913</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/08ed41f339e345286f26bdbc6c67bf9f2975ed07"><code>08ed41f</code></a> chore: fix typos (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3907">#3907</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/90e1935c486417ec64507b26ff4bf80a3dfb19e2"><code>90e1935</code></a> test: test with tracing (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3906">#3906</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/b877629cb1678132611211b43b4b9e1b879e6b20"><code>b877629</code></a> net: handle HUP event with UnixStream (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3898">#3898</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/0531549b6ea66d22d301044910ddc6a77e8c7f1e"><code>0531549</code></a> io: efficient implementation of vectored writes for BufWriter (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3163">#3163</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/38204f5fbacb4ef5dc30a407609bd3ae50aef717"><code>38204f5</code></a> time: fix Timeout size_hint (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3902">#3902</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/8fa29cb00a486c0ffc28f295c749573cb58a8967"><code>8fa29cb</code></a> rt: add tokio::task::Builder (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3881">#3881</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/b521cc26895c6331c8ced6be72f8b3d9947a9fb3"><code>b521cc2</code></a> doc: document cancellation safety (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3900">#3900</a>)</li>
<li><a href="https://github.com/tokio-rs/tokio/commit/57c90c9750d02c5bca93a939c7d44d7fe74fe464"><code>57c90c9</code></a> net: add read/try_read etc methods to NamedPipeServer (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3899">#3899</a>)</li>
<li>Additional commits viewable in <a href="https://github.com/tokio-rs/tokio/compare/tokio-1.5.0...tokio-1.8.0">compare view</a></li>
</ul>
</details>
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