Use Yarn in CI cache

wincent · wincent · commit 75d6ddd45174 · 2017-01-26T16:15:35.000-08:00
Should give us faster builds.
diff --git a/.travis.yml b/.travis.yml
@@ -9,9 +9,7 @@ node_js:
 git:
   depth: 5
 
-cache:
-  directories:
-    - ~/.npm
+cache: yarn
 
 before_install:
   - npm config set spin false --global
