Update base64 requirement from 0.21.0 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@v0.21.0...v0.22.0)

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

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

tsar-rs/Cargo.toml

@@ -8,7 +8,7 @@ name = "tsar"
 path = "src/lib.rs"
 
 [dependencies]
-base64 = "0.21.0"
+base64 = "0.22.0"
 half = { version = "2.1.0", features = ["num-traits"] }
 num-traits = "0.2.15"
 protobuf = "3.1.0"