Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/check-pr.yaml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Set up JDK 17
         uses: actions/setup-java@v5
@@ -29,7 +29,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Set up JDK 17
         uses: actions/setup-java@v5