minimal-versions: run tests using stable Rust

[tarcieri]

Adds a configurable toolchain parameter to the reusable workflow for minimal-versions which allows a different toolchain than nightly to be used for the purposes of running tests.

nightly is only needed for the -Z minimal-versions resolution of Cargo.lock. We can avoid nightly breakages of which we've hit quite a few lately by reducing the scope of what we use nightly for to just that version resolution.

Additionally, this moves the resolution of Cargo.lock to earlier in the workflow so it applies to all steps. Previously benchmarks were being tested before the -Z minimal-versions resolution took place.

[tarcieri]

FWIW I think using cargo hack in this workflow is overkill and means it can't be used with crates that have a large number of features due to the combinatorial explosion.

I think we could get by with just testing a few different feature combinations like --no-default-features, default features, and --all-features

[newpavlov]

FWIW I think using cargo hack in this workflow is overkill and means it can't be used with crates that have a large number of features due to the combinatorial explosion.

It may be worth to make the test command a configurable parameter as well, with the cargo hack test being the default.

[tarcieri]

It may be worth to make the test command a configurable parameter as well, with the cargo hack test being the default.

I feel like cargo hack requires a lot of maintenance and planning, where the purpose of this workflow is merely to ensure that the library works with minimal dependencies. Honestly I feel like cargo hack is major overkill here, and even cargo build or even cargo check would be sufficient.

I've been dealing with many, many subprojects that have excessively long minimal-versions workflows, and in many cases simply abandoned the shared action for a more minimalist check, which seems to defeat the point. The default should be easy-to-use and cover all cases. In many of these cases minimal-versions is the last job to complete, by far, and just clogging up CI workflows.

[newpavlov]

--each-feature being the default may address your concerns. I think we should test all features, but you are right that testing all combinations in a minimal versions job is probably a tad excessive.

[tarcieri]

Ran into another seemingly nightly-related failure, so hopefully this fixes it: https://github.com/RustCrypto/traits/actions/runs/6837021752/job/18592552010