chore: update GitHub Actions CI

[striezel]

The following updates are performed:

• update actions/checkout to v4
• replace unmaintained actions-rs/toolchain by dtolnay/rust-toolchain
• replace unmaintained actions-rs/cargo by direct invocation of cargo

Still using the outdated / unmaintained actions will generate several warnings in CI runs, for example in https://github.com/tower-rs/tower/actions/runs/4995991400:

Node.js 12 actions are deprecated. Please update the following actions to use Node.js 16: actions-rs/toolchain@v1, actions-rs/cargo@v1. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/.

The PR will get rid of those warnings.

[GlenDC]

LGTM
wasn't aware of this change in the ecosystem,
but double checking docs at https://github.com/dtolnay/rust-toolchain and other info I found seems to back the incentive behind this PR.

[striezel]

wasn't aware of this change in the ecosystem, but double checking docs at https://github.com/dtolnay/rust-toolchain and other info I found seems to back the incentive behind this PR.

In the mean time, the whole actions-rs organization has been archived. If the lack of maintainer activity in the repos over there was not enough of a hint that nothing is going to happen there anymore, then that step finally settled it for good.

So yeah ... I think everyone who is still using actions-rs/toolchain etc. should move to an alternative as soon as possible.

[striezel]

@hawkw @GlenDC Any updates on this one? Looks like some of the checks have not even started yet, so I guess that maybe someone has to approve them in order for them to run?

[GlenDC]

@tobz this is also a trivial one to merge, no? Or am I missing something?

[tobz]

Yeah, this is probably fine to merge as-is... although it's another case where the PR branch is out-of-date and I can't trivially update it.

[striezel]

although it's another case where the PR branch is out-of-date and I can't trivially update it.

It's been over a year, so that's no surprise. I almost got the impression the project had been abandoned due to the lack of activity here.

Anyway, I rebased the branch against the current master so this should be easier to merge now.