build(deps): update rustls requirement from 0.20.8 to 0.21.8

Updates the requirements on [rustls](https://github.com/rustls/rustls) to permit the latest version.
- [Release notes](https://github.com/rustls/rustls/releases)
- [Commits](rustls/rustls@v/0.20.8...v/0.21.8)

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

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

Cargo.toml

@@ -27,7 +27,7 @@ lazy_static = "1.4.0"
 log = "0.4"
 env_logger = "0.10.0"
 reqwest = {version = "0.11.14",features = ["socks","brotli","gzip","deflate","rustls-tls"]}
-rustls = "0.20.8"
+rustls = "0.21.8"
 rustls-pemfile = "1.0.2"
 
 [profile.fast]