Upgrade to actions/checkout v6

Author: carlosame

.github/workflows/build.yml

@@ -20,7 +20,7 @@ jobs:
     name: Validate Gradle wrapper
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: gradle/actions/wrapper-validation@v5
 
   build:
@@ -34,7 +34,7 @@ jobs:
 
     steps:
       # Checks-out the repository under $GITHUB_WORKSPACE
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       # Set JDK
       - name: Set up JDK