Bump mio from 0.7.14 to 0.8.0

Bumps [mio](https://github.com/tokio-rs/mio) from 0.7.14 to 0.8.0.
- [Release notes](https://github.com/tokio-rs/mio/releases)
- [Changelog](https://github.com/tokio-rs/mio/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tokio-rs/mio/compare/v0.7.14...v0.8.0)

---
updated-dependencies:
- dependency-name: mio
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.lock

@@ -693,9 +693,9 @@ checksum = "a3e378b66a060d48947b590737b30a1be76706c8dd7b8ba0f2fe3989c68a853f"
 
 [[package]]
 name = "mio"
-version = "0.7.14"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8067b404fe97c70829f082dec8bcf4f71225d7eaea1d8645349cb76fa06205cc"
+checksum = "ba272f85fa0b41fc91872be579b3bbe0f56b792aa361a380eb669469f68dafb2"
 dependencies = [
  "libc",
  "log",