Update base64-serde requirement from 0.7 to 0.8 (#326)

Updates the requirements on [base64-serde](https://github.com/marshallpierce/base64-serde) to permit the latest version.
- [Changelog](https://github.com/marshallpierce/base64-serde/blob/master/RELEASE-NOTES.md)
- [Commits](marshallpierce/base64-serde@v0.7.0...v0.8.0)

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

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

Cargo.toml

@@ -20,7 +20,7 @@ rust-version = "1.75.0"
 
 [dependencies]
 base64 = "0.22"
-base64-serde = "0.7"
+base64-serde = "0.8"
 bytes = "1"
 dashmap = "6"
 futures = "0.3.1"