Update actions/checkout action to v6

Author: xdev-renovate

.github/workflows/check-build.yml

@@ -89,7 +89,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 30
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up JDK
       uses: actions/setup-java@v5