feat(ci): add a format and msrv step

[Totodore]

Add a format step and an msrv step, inspired from a crate repo I'm maintaining: https://github.com/Totodore/socketioxide/blob/main/.github/workflows/github-ci.yml

Happy to make any change.

Every rust change is only the result of cargo fmt

[Totodore]

I didn't see the msrv.yml separate pipeline, should I remove the change in rust.yml or the msrv.yml?

[Totodore]

Also, I'd like to add a clippy step to improve the codebase sanity once this is merge

[gagantrivedi]

I didn't see the msrv.yml separate pipeline, should I remove the change in rust.yml or the msrv.yml?

Yes, please drop the msrv.yml

[Totodore]

1.86 as an MSRV seems to not be longer valid because of an implicit bump that lead to a breaking change. Usually Cargo.lock should be commited to avoid these kind of breaking changes.

[gagantrivedi]

1.86 as an MSRV seems to not be longer valid because of an implicit bump that lead to a breaking change. Usually Cargo.lock should be commited to avoid these kind of breaking changes.

That's a fair point — if we have an MSRV check, we probably should add the lock file as well! Happy to accept it as part of this pull request.