chore(deps): bump base64 from 0.20.0 to 0.21.0 (#279)

Bumps [base64](https://github.com/marshallpierce/rust-base64) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/marshallpierce/rust-base64/releases)
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](https://github.com/marshallpierce/rust-base64/compare/v0.20.0...v0.21.0)

---
updated-dependencies:
- dependency-name: base64
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Cargo.lock

@@ -51,9 +51,9 @@ checksum = "9e1b586273c5702936fe7b7d6896644d8be71e6314cfe09d3167c95f712589e8"
 
 [[package]]
 name = "base64"
-version = "0.20.0"
+version = "0.21.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ea22880d78093b0cbe17c89f64a7d457941e65759157ec6cb31a31d652b05e5"
+checksum = "a4a4ddaa51a5bc52a6948f74c06d20aaaddb71924eab79b8c97a8c556e942d6a"
 
 [[package]]
 name = "bb8"
@@ -661,7 +661,7 @@ version = "0.6.0-alpha1"
 dependencies = [
  "arc-swap",
  "async-trait",
- "base64 0.20.0",
+ "base64 0.21.0",
  "bb8",
  "bytes",
  "chrono",