Added gradle wrapper generation

Author: Vitaliy Boyko

.github/workflows/gradle.yml

@@ -20,6 +20,10 @@ jobs:
       uses: actions/setup-java@v1
       with:
         java-version: 1.8
+    - name: Grant execute permission for gradle
+      run: chmod +x gradle
+    - name: Generate wrapper
+      run: gradle wrapper
     - name: Grant execute permission for gradlew
       run: chmod +x gradlew
     - name: Run automated tests