Update tokio-rustls to v0.23

[olix0r]

This change bumps the tokio-rustls version to pick up the new version of
rustls.

This helps to avoid duplicate dependencies when using other libraries
that depend on rustls.

[olix0r]

@seanmonstar I fixed the server config builder to use the newer types. PTAL :)

[olix0r]

These errors could be handled as TlsConfigError::Io now, but I didn't want to change the public API more than needed.

[olix0r]

e0cc66c removed what seemed like a bad semicolon (because nightly tests failed, iirc). I've reverted that change and confirmed tests pass locally. nightly tests might fail again, though 🤷

[olix0r]

OK, the beta build fails with

2021-12-29T16:58:33.6376879Z failures:
2021-12-29T16:58:33.6377235Z 
2021-12-29T16:58:33.6377924Z ---- src/reject.rs - reject (line 25) stdout ----
2021-12-29T16:58:33.6380166Z error: expected item, found `;`
2021-12-29T16:58:33.6392473Z ##[error] --> src/reject.rs:31:44
2021-12-29T16:58:33.6411477Z   |
2021-12-29T16:58:33.6412021Z 8 | impl reject::Reject for InvalidParameter {};
2021-12-29T16:58:33.6412617Z   |                                            ^ help: remove this semicolon
2021-12-29T16:58:33.6412950Z 
2021-12-29T16:58:33.6413457Z error: aborting due to previous error
2021-12-29T16:58:33.6414378Z ##[error]aborting due to previous error
2021-12-29T16:58:33.6415873Z Couldn't compile the test.
2021-12-29T16:58:33.6416190Z 
2021-12-29T16:58:33.6416498Z failures:
2021-12-29T16:58:33.6417060Z     src/reject.rs - reject (line 25)
2021-12-29T16:58:33.6417372Z 
2021-12-29T16:58:33.6417939Z test result: FAILED. 112 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 56.21s
2021-12-29T16:58:33.6418430Z 
2021-12-29T16:58:33.6418994Z error: test failed, to rerun pass '--doc'
2021-12-29T16:58:33.6452587Z ##[error]The process '/home/runner/.cargo/bin/cargo' failed with exit code 101

Pretty sure this is broken on master, though. Removing this semicolon causes the stable build to hang.

[seanmonstar]

Yup, found the hang, fixed in master and merged in here so we can go green and merge.