Bump base64 from 0.21.3 to 0.21.4

Bumps [base64](https://github.com/marshallpierce/rust-base64) from 0.21.3 to 0.21.4.
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](marshallpierce/rust-base64@v0.21.3...v0.21.4)

---
updated-dependencies:
- dependency-name: base64
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

Cargo.lock

@@ -39,7 +39,7 @@ ahash = "0.8.0"
 url = "2.4.1"
 # idna is already required by url, added here to be explicit
 idna = "0.4.0"
-base64 = "0.21.3"
+base64 = "0.21.4"
 num-bigint = "0.4.4"
 python3-dll-a = "0.2.7"
 uuid = "1.4.1"