Auto merge of #49590 - alexcrichton:update-deps, r=Mark-Simulacrum

Bump to 1.27.0

Also update some `Cargo.lock` dependencies, finishing up some final steps of our
[release process]!

This doesn't update the bootstrap compiler just yet but that will come in a
follow-up PR.

[release process]: https://forge.rust-lang.org/release-process.html

Author: bors