Only run travis on master branch (flutter#70)

natebosch · web-flow · commit 9f081c7d84bf · 2018-02-15T19:01:35.000-08:00
diff --git a/.travis.yml b/.travis.yml
@@ -10,6 +10,9 @@ dart_task:
   - dartanalyzer
   - dartfmt
 
+branches:
+  only: [master]
+
 matrix:
   # Only run dartfmt checks with stable.
   exclude:
