fix(ci): give release-plz the ALSA dev package that git_only now needs

[filipeforattini]

Follow-up to #46. That PR worked — the run log went from silently skipping the package to:

INFO Latest release of package dit: tag `v0.3.1` (version 0.3.1)

so git_only is reading versions from git tags as intended. But it then failed:

0: failed to determine next versions
1: run cargo package
   error: failed to run custom build command for `alsa-sys v0.3.1`
   The system library `alsa` required by crate `alsa-sys` was not found.

Cause

git_only compares the working tree against the tagged release using cargo package, and cargo package verifies by building. That pulls in alsa-sys, whose build script panics without libasound.

release-plz.yml is the one job that never installed it — before git_only it never compiled anything, it just read metadata. ci.yml and release.yml both already install libasound2-dev pkg-config.

Note

This is a loud failure, not the silent-green idling from #46 — the workflow went red and stayed red. The Flag a silent no-op guard correctly did not fire, since it only speaks when release-plz succeeds while proposing nothing.

Upstream tracks the underlying brittleness in release-plz #2789 ("fall back to source dir comparison when cargo package fails"). Installing the dep sidesteps it rather than waiting on it.

Verification

Same as #46: config-only, so the proof is the next run on main. Merging this should produce a chore: release v0.3.2 release PR. I will report what actually happens rather than assume.

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