Gradle caching and validation

.github/workflows/gradle.yml

@@ -10,17 +10,31 @@ on:
     branches: [ master ]
 
 jobs:
-  build:
-
+  validation:
     runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: gradle/wrapper-validation-action@v1
 
+  build:
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
     - name: Set up JDK 11
       uses: actions/setup-java@v2
       with:
         java-version: '11'
         distribution: 'adopt'
+    - uses: actions/cache@v2
+      with:
+        path: ~/.gradle/wrapper
+        key: ${{ runner.os }}-gradle-wrapper-${{ hashFiles('gradle/wrapper/gradle-wrapper.properties') }}
+    - uses: actions/cache@v2
+      with:
+        path: ~/.gradle/caches
+        key: ${{ runner.os }}-gradle-caches-${{ hashFiles('gradle/wrapper/gradle-wrapper.properties') }}
+        restore-keys: |
+          ${{ runner.os }}-gradle-caches-
     - name: Grant execute permission for gradlew
       run: chmod +x gradlew
     - name: Build with Gradle