build(deps): update base64 requirement from 0.21.2 to 0.22.0

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@v0.21.2...v0.22.0)

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

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

Cargo.toml

@@ -12,7 +12,7 @@ keywords = ["merkle", "tree", "crdt", "anti-entropy", "hash"]
 categories = ["data-structures", "cryptography"]
 
 [dependencies]
-base64 = { version = "0.21.2", optional = true }
+base64 = { version = "0.22.0", optional = true }
 siphasher = "1.0.0"
 tracing = { version = "0.1.37", optional = true }