Update base64 requirement from 0.13.0 to 0.20.0

Updates the requirements on [base64](https://github.com/marshallpierce/rust-base64) to permit the latest version.
- [Release notes](https://github.com/marshallpierce/rust-base64/releases)
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](marshallpierce/rust-base64@v0.13.0...v0.20.0)

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

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

kube-client/Cargo.toml

@@ -36,7 +36,7 @@ features = ["client", "rustls-tls", "openssl-tls", "ws", "oauth", "jsonpatch", "
 rustdoc-args = ["--cfg", "docsrs"]
 
 [dependencies]
-base64 = { version = "0.13.0", optional = true }
+base64 = { version = "0.20.0", optional = true }
 chrono = { version = "0.4.23", optional = true, default-features = false }
 dirs = { package = "dirs-next", optional = true, version = "2.0.0" }
 serde = { version = "1.0.130", features = ["derive"] }