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](https://github.com/marshallpierce/rust-base64/compare/v0.21.0...v0.22.1)

---
updated-dependencies:
- dependency-name: base64
  dependency-version: 0.22.1
  dependency-type: direct:production
...

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

Cargo.toml

@@ -38,7 +38,7 @@ panic = 'abort'
 aes-gcm = "0.10"
 anyhow = "1.0"
 argon2 = "0.5"
-base64 = "0.21"
+base64 = "0.22"
 bincode = "1.3"
 blake3 = "1.3"
 hex = "0.4"