Update base64 requirement from 0.21 to 0.22 (#318)

Updates the requirements on [base64](https://github.com/marshallpierce/rust-base64) to permit the latest version.
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](marshallpierce/rust-base64@v0.21.0...v0.22.0)

---
updated-dependencies:
- dependency-name: base64
  dependency-type: direct:production
...

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

Cargo.toml

@@ -20,7 +20,7 @@ rust-version = "1.74.0"
 
 [dependencies]
 async-trait = "0.1.21"
-base64 = "0.21"
+base64 = "0.22"
 base64-serde = "0.7"
 bytes = "1"
 dashmap = "5"