Bump prefix-dev/setup-pixi from 0.8.3 to 0.8.4 (#474)

Bumps [prefix-dev/setup-pixi](https://github.com/prefix-dev/setup-pixi) from 0.8.3 to 0.8.4.
- [Release notes](https://github.com/prefix-dev/setup-pixi/releases)
- [Commits](prefix-dev/setup-pixi@v0.8.3...v0.8.4)

---
updated-dependencies:
- dependency-name: prefix-dev/setup-pixi
  dependency-version: 0.8.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build-test.yml

@@ -42,7 +42,7 @@ jobs:
           echo PR_COMMIT_MESSAGE=$(git log -1 --pretty=format:\"%s\") >> $GITHUB_ENV
         shell: bash
 
-      - uses: prefix-dev/setup-pixi@v0.8.3
+      - uses: prefix-dev/setup-pixi@v0.8.4
         with:
           pixi-version: v0.39.5
           environments: ${{ matrix.environment }}