Update actions/checkout action to v3

Author: renovate[bot]

.github/workflows/gradle-build.yml

@@ -16,7 +16,7 @@ jobs:
     steps:
       # Checkout the Code
       - name: Checkout Code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       # Set up git hashes environment variables
       - name: Git Hashes
         uses: Im-Fran/git-hashes-action@v1.0.0

.github/workflows/gradle-test.yml

@@ -16,7 +16,7 @@ jobs:
     steps:
     # Checkout code
     - name: Checkout Code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
     # Setup java and maven
     - name: Set up JDK ${{ matrix.java-version }}
       uses: actions/setup-java@v3

.github/workflows/gradle-wrapper-validation.yml

@@ -6,5 +6,5 @@ jobs:
     name: "Validation"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: gradle/wrapper-validation-action@v1