GitHub CI using deprecated actions

[cpu]

The CI workflows are currently using actions-rs tasks that are unmaintained and affected by GitHub's deprecation of Node 12.

The following actions uses node12 which is deprecated and will be forced to run on node16: actions-rs/toolchain@v1, actions-rs/cargo@v1. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/

The following workflow task need to be replaced:

• actions-rs/toolchain@v1 used by ci.yaml
• actions-rs/cargo@v1 used by ci.yaml
• actions-rs/audit-check@v1 used by audit.yml

In the other Rustls projects we've switched to https://github.com/dtolnay/rust-toolchain, but it doesn't offer an equivalent to audit-check. That one might require a separate 3rd party action.

[complexspaces]

audit-check is small enough we could probably utilize GitHub Actions cache and a manual cargo-install to accomplish the same thing. I'm in favor of migrating the other ones to Dtolnay's.

[djc]

What does audit-check do? Can we just pick up cargo-deny? It consumes the advisory database and helps with a bunch of other stuff, too.

[complexspaces]

I see cargo-deny as a superset of cargo-audit, so I don't see an issue with that if we have an easy way to utilize it in CI.

[djc]

#29 replaces audit-check with cargo-deny.