Bump mio from 0.8.3 to 0.8.4 (#89)

Bumps [mio](https://github.com/tokio-rs/mio) from 0.8.3 to 0.8.4.
- [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/v0.8.3...v0.8.4)

---
updated-dependencies:
- dependency-name: mio
  dependency-type: indirect
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.lock

@@ -926,9 +926,9 @@ dependencies = [
 
 [[package]]
 name = "mio"
-version = "0.8.3"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "713d550d9b44d89174e066b7a6217ae06234c10cb47819a88290d2b353c31799"
+checksum = "57ee1c23c7c63b0c9250c339ffdc69255f110b298b901b9f6c82547b7b87caaf"
 dependencies = [
  "libc",
  "log",