dependencies: Update salsa to 0.20.0

[CreatedBySeb]

Summary

Updates salsa to 0.20.0 as a crate dependency, rather than a git dependency. The previous version was salsa-rs/salsa@87bf6b6, which is included in the 0.20.0 release (salsa-rs/salsa#753).

Removing one of the two git dependencies in Ruff removes a blocker to #43, and given the crates release for salsa is ahead of the depended upon git commit, this seems like a good time to make the swap.

Test Plan

Since this is a dependency change rather than a functional change, I followed the testing from the Contributing docs on both an M1 MacBook Air and an AMD Linux machine.

cargo clippy --workspace --all-targets --all-features -- -D warnings
RUFF_UPDATE_SCHEMA=1 cargo nextest run
uvx pre-commit run --all-files --show-diff-on-failure

I used nextest rather than regular test per advice earlier in the guide, but did also try RUFF_UPDATE_SCHEMA=1 cargo test on the Linux machine in case there was any difference.

I was not sure what the correct way to use the fuzzers to test this change might be, since the information on how to use them wasn't very clear to me.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

Formatter (stable)

✅ ecosystem check detected no format changes.

Formatter (preview)

✅ ecosystem check detected no format changes.

[MichaReiser]

Thanks for the PR.

We're getting close to switching to the crates.io Salsa dependency but there have still been multiple recent occasions where we had to fix a bug in Salsa and the git dependency allowed us to move faster because of it. That's why I want to keep the git dependency for a little longer until things on the salsa side settle down.

[manmartgarc]

have things settled down yet?

[MichaReiser]

No