Update actions/checkout action to v5

Author: renovate[bot]

.github/workflows/gradle.yml

@@ -13,7 +13,7 @@ jobs:
     timeout-minutes: 15
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
 
     - name: Set up JDK 17
       uses: actions/setup-java@v5