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] <support@github.com>

Author: dependabot[bot]

postgres-protocol/Cargo.toml

@@ -13,7 +13,7 @@ default = []
 js = ["getrandom/js"]
 
 [dependencies]
-base64 = "0.21"
+base64 = "0.22"
 byteorder = "1.0"
 bytes = "1.0"
 fallible-iterator = "0.2"