Merge pull request #47 from squeed/bump-go

travis: bump go

.travis.yml

@@ -3,13 +3,9 @@ sudo: required
 dist: trusty
 
 go:
-  - 1.5.x
-  - 1.6.x
-  - 1.7.x
-  - 1.8.x
   - 1.9.x
+  - 1.10.x
   - tip
-
 env:
   global:
     - TOOLS_CMD=golang.org/x/tools/cmd