fix: Use npm v5 on CI (#18)

ajsharp · Andrey Okonetchnikov · commit 30b668fd0306 · 2018-02-07T21:01:07.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -10,7 +10,7 @@ node_js:
   - '6'
   - '4'
 before_install:
-  - npm i -g npm@^2.0.0
+  - npm i -g npm@^5.0.0
 before_script:
   - npm prune
 after_success:
