chore: update build tools to 27.0.3

Author: tgpetrov

.travis.yml

@@ -39,7 +39,7 @@ android:
   components:
     - tools
     - platform-tools
-    - build-tools-26.0.2
+    - build-tools-27.0.3
     - android-26
     - android-23
     - extra-android-m2repository