Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/build.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name : Validate Gradle Wrapper
         uses: gradle/actions/wrapper-validation@v5
       - name: Setup Java

.github/workflows/codeql.yml

@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v4