Bump log from 0.4.20 to 0.4.21

Bumps [log](https://github.com/rust-lang/log) from 0.4.20 to 0.4.21.
- [Release notes](https://github.com/rust-lang/log/releases)
- [Changelog](https://github.com/rust-lang/log/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/log/compare/0.4.20...0.4.21)

---
updated-dependencies:
- dependency-name: log
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Cargo.lock

@@ -138,9 +138,9 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.20"
+version = "0.4.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+checksum = "90ed8c1e510134f979dbc4f070f87d4313098b704861a105fe34231c70a3901c"
 
 [[package]]
 name = "memchr"