CI: bump actions/cache

Author: Christoph Lehmann

.github/workflows/ci.yml

@@ -32,7 +32,8 @@ jobs:
         run: composer validate
 
       - name: Cache dependencies
-        uses: actions/cache@v1
+        id: composer-dependencies
+        uses: actions/cache@v4
         with:
           path: ~/.composer/cache
           key: dependencies-composer-${{ hashFiles('composer.json') }}