Update to tokio 1.0

[MonsieurMan]

Hi there !

I'll be using your library for a little raspberry project, checking tokyo I see there is a new version.

I'm in need of a little more training in Rust, would you be interested in me landing a PR for a migration to tokyo 0.3, or are there any current work on the matter ?

Thanks in advance,

[jonhoo]

Hi! Absolutely, I'd love one. I think we're probably going to be blocked on hyper not yet supporting tokio 0.3, but getting the ball rolling is a good idea :)

[MonsieurMan]

hyper author is going to wait a few weeks for tokio 1.0 to ship, in order not to burden his users with potentially two breaking releases.
So you're right, I can do some preparation work, but it won't be finished until tokio 1.0 and hyper 0.14

[jonhoo]

Now that tokio 1.0 and hyper 0.14 are out, I think we're only blocked on hyper-tls to get this out the door (hyperium/hyper-tls#76)!

[jonhoo]

See also https://bugzilla.mozilla.org/show_bug.cgi?id=1684226

[nc7s]

And tokio 1.0 was released. What a pace for them.

[peppizza]

hyper-tls v0.5 has been released with tokio 1.0, so if that was the last thing blocking then we should be free to update this lib

[jonhoo]

We unfortunately also currently have warp as a dev-dependency, which is still on tokio 0.2 (issue here: seanmonstar/warp#725). If someone wants to submit a PR that moves the tests to use hyper for the server instead (shouldn't be too painful), then that would unblock the move!

[jonhoo]

#118