Add a CI Check that fails if Spotless does not pass, to enforce project style guidelines.

I will also show how to fix things running ./gradlew spotlessApply

Signed-off-by: Alfredo Gutierrez <[email protected]>

Author: AlfredoG87

.github/workflows/spotless-check.yml

@@ -0,0 +1,43 @@
+name: Spotless Check
+
+on: [pull_request]
+
+jobs:
+  spotless:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@17d0e2bd7d51742c71671bd19fa12bdc9d40a3d6 # v2.8.1
+        with:
+          egress-policy: audit
+
+      - name: Checkout code
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+        with:
+          fetch-depth: 0
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9 # v4.2.1
+        with:
+          distribution: 'temurin'
+          java-version: '21'
+
+      - name: Cache Gradle packages
+        uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9 # v4.0.2
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Run Spotless Check
+        run: |
+          ./gradlew spotlessCheck
+          if [ $? -ne 0 ]; then
+            echo "Spotless found formatting issues. Please run './gradlew spotlessApply' to fix them."
+            exit 1
+          fi
+        continue-on-error: false