add gradle wrapper validation action to workflows (#99)

.github/workflows/Build.yaml

@@ -18,6 +18,9 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
 
+      - name: Validate Gradle Wrapper
+        uses: gradle/wrapper-validation-action@v1
+
       - name: Copy CI gradle.properties
         run: mkdir -p ~/.gradle ; cp .github/ci-gradle.properties ~/.gradle/gradle.properties        
 

.github/workflows/Release.yml

@@ -14,6 +14,9 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2   
 
+      - name: Validate Gradle Wrapper
+        uses: gradle/wrapper-validation-action@v1
+
       - name: Copy CI gradle.properties
         run: mkdir -p ~/.gradle ; cp .github/ci-gradle.properties ~/.gradle/gradle.properties