Add cache for gradle

Cache dependencies based on gradle.properties.
Avoids redownloading on every build

Author: RobertLK

.github/workflows/android.yml

@@ -8,6 +8,14 @@ jobs:
 
     steps:
     - uses: actions/checkout@v1
+    - name: Cache gradle dependencies
+      uses: actions/cache@v1
+      with:
+        path: ~/.gradle
+        key: ${{ runner.os }}-gradle-${{ hashFiles('gradle.properties') }}
+        restore-keys: |
+          ${{ runner.os }}-gradle-
+          ${{ runner.os }}-
     - name: set up JDK 1.8
       uses: actions/setup-java@v1
       with: