Fix Android SDK license issue

* accept sdk licenses before run script

Author: kaozaza2

.travis.yml

@@ -45,6 +45,7 @@ cache:
 before_script:
  - cp -f app/mock-google-services.json app/google-services.json
  - cat app/keys.properties.example | envsubst > app/keys.properties
+ - yes | sdkmanager --licenses
 
 script:
 # - ./gradlew connectedAndroidTest --stacktrace -w