Differentiate GitHub Actions build

.github/workflows/android_ci.yml

@@ -2,9 +2,9 @@ name: Android CI
 
 on:
   push:
-    branches: [ develop ]
-  pull_request:
-    branches: [ develop ]
+    branches:
+      - develop
+      - master
 
 jobs:
   build:

.github/workflows/build.yml

@@ -0,0 +1,26 @@
+name: Gradle Build
+
+on:
+  pull_request:
+    branches:
+      - develop
+      - master
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: set up JDK 8
+      uses: actions/setup-java@v2
+      with:
+        java-version: '8'
+        distribution: 'adopt'
+        cache: gradle
+
+    - name: Grant execute permission for gradlew
+      run: chmod +x gradlew
+    - name: Build with Gradle
+      run: ./gradlew build