ci: use gradle cache and checkout v4

quarkus/.github/workflows/ci.yml

@@ -12,12 +12,12 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
           java-version: 21
           distribution: temurin
-          cache: maven
+          cache: gradle
       - name: Build
         run: ./gradlew build