Add git config to travis script

Author: kuoruan

.travis.yml

@@ -36,6 +36,10 @@ android:
 notifications:
   email: false
 
+git:
+  depth: 1
+  submodules: false
+
 before_install:
   - yes | sdkmanager "platforms;android-27"
   - openssl aes-256-cbc -K $encrypted_fe6090d19007_key -iv $encrypted_fe6090d19007_iv -in chrome.jks.enc -out chrome.jks -d