Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/maven.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3.5.3
+    - uses: actions/checkout@v4.1.7
     - name: Set up JDK 16
       uses: actions/setup-java@v3.11.0
       with: