Update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/maven.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: "Set up JDK"
         uses: actions/setup-java@v5
         with: