Replace Travis CI with GH Actions

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-gradle
+
+name: Java CI with Gradle
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - '**'
+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'
+    - name: Grant execute permission for gradlew
+      run: chmod +x gradlew
+    - name: Build with Gradle
+      run: ./gradlew build
+    - run: pip install --user codecov
+    - run: mkdir "$ANDROID_HOME/licenses" || true
+    - run: echo "24333f8a63b6825ea9c5514f83c2829b004d1fee" >> "$ANDROID_HOME/licenses/android-sdk-license"
+    - run: ./gradlew clean testDebugUnitTest jacocoTestReport