Use sdkmanager to approve licenses

Author: Jawnnypoo

.travis.yml

@@ -10,8 +10,7 @@ jdk:
 
 before_install:
     - pip install --user codecov
-    - mkdir "$ANDROID_HOME/licenses" || true
-    - echo "d56f5187479451eabf01fb78af6dfcb131a6481e" > "$ANDROID_HOME/licenses/android-sdk-license"
+    - yes | sdkmanager --licenses
 
 script:
   - ./gradlew clean testDebugUnitTest jacocoTestReport