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>

opensearch/Cargo.toml

@@ -30,7 +30,7 @@ aws-auth = ["aws-credential-types", "aws-sigv4", "aws-smithy-runtime-api", "aws-
 
 [dependencies]
 async-trait = "0.1"
-base64 = "0.21"
+base64 = "0.22"
 bytes = "1.0"
 dyn-clone = "1"
 lazy_static = "1.4"

yaml_test_runner/Cargo.toml

@@ -13,7 +13,7 @@ opensearch = { path = "../opensearch", features = ["experimental-apis"]}
 api_generator = { path = "./../api_generator" }
 
 anyhow = "1.0"
-base64 = "0.21"
+base64 = "0.22"
 clap = "2"
 itertools = "0.12.0"
 Inflector = "0.11.4"