Update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/mvntest.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Set up JDK 17
         uses: actions/setup-java@v5
         with: