Update GH Actions

Author: Sigri44

.github/workflows/alpha.yml

@@ -56,7 +56,7 @@ jobs:
               run: echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
 
             - name: Cache composer dependencies
-              uses: actions/cache@v3
+              uses: actions/cache@v4
               with:
                   path: ${{ steps.composer-cache.outputs.dir }}
                   # Use composer.json for key, if composer.lock is not committed.