Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/maven-publish.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Set up JDK 11
         uses: actions/setup-java@v3
         with: