Before install instead of before script

Author: Jawnnypoo

.travis.yml

@@ -8,7 +8,7 @@ android:
     - platform-tools
     - tools
 
-before_script:
+before_install:
   # Install SDK license so Android Gradle plugin can install deps.
   - mkdir "$ANDROID_HOME/licenses" || true
   - echo "8933bad161af4178b1185d1a37fbf41ea5269c55" > "$ANDROID_HOME/licenses/android-sdk-license"