Update base64 requirement from 0.21 to 0.22

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]>

Cargo.toml

@@ -12,7 +12,7 @@ keywords = ["tracing", "elastic", "apm", "telemetry"]
 license = "MIT"
 
 [dependencies]
-base64 = "0.21"
+base64 = "0.22"
 fxhash = "0.2"
 rand = "0.8"
 reqwest = { version = "0.11", default-features = false, features = [] }