Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/build-pr.yml

@@ -9,7 +9,7 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-latest]
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Validate Gradle Wrapper
         uses: gradle/wrapper-validation-action@v3
       - name: Setup Java

.github/workflows/release.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Validate Gradle Wrapper
         uses: gradle/wrapper-validation-action@v3
       - name: Setup Java