Upgrade TLS libraries and code

[sarajmunjal]

What

Upgraded tokio-rustls, rustls and rustls-pemfile to newer version
Also needed to add an import on rustls-pki-types because some constants are not available.

Why

Am trying to build pgcat inside a private repository with newer dependency versions.

Details

Because there were breaking changes, I had to follow some resources and examples from other projects.
https://github.com/rustls/rustls/releases/tag/v%2F0.22.0 - see Breaking Changes section.

Other examples

1. https://github.com/rustls/rustls/blob/main/examples/src/bin/tlsclient-mio.rs
2. https://github.com/rbatis/rbatis/blob/master/rbdc/src/net/tls/rustls.rs

Help needed

I could use some help with testing. Is there a testcase related to certs in the CI suite?

[drdrsh]

I ran the the test suite against your PR, there are some linting issues there.

[sarajmunjal]

Thanks, this was because I had run just update - that bumped up many things in the lockfile and led to deprecation warnings. I have undone this, and now the Cargo.lock change is bare minimum updates associated with Cargo.toml changes.

cargo clippy passes now.

Can we run tests again?