Bump prefix-dev/setup-pixi in the github-actions group

Bumps the github-actions group with 1 update: [prefix-dev/setup-pixi](https://github.com/prefix-dev/setup-pixi).


Updates `prefix-dev/setup-pixi` from 0.9.3 to 0.9.4
- [Release notes](https://github.com/prefix-dev/setup-pixi/releases)
- [Commits](prefix-dev/setup-pixi@v0.9.3...v0.9.4)

---
updated-dependencies:
- dependency-name: prefix-dev/setup-pixi
  dependency-version: 0.9.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/main.yaml

@@ -43,7 +43,7 @@ jobs:
             environment: py313
     steps:
       - uses: actions/checkout@v6
-      - uses: prefix-dev/[email protected].3
+      - uses: prefix-dev/[email protected].4
         with:
           pixi-version: v0.62.2
           cache: true