chore: fix link to Nightwatch (#1218)

Patrick Lewis · yyx990803 · commit dfbb871df887 · 2018-05-03T14:17:35.000-04:00
diff --git a/packages/@vue/cli-plugin-e2e-nightwatch/README.md b/packages/@vue/cli-plugin-e2e-nightwatch/README.md
@@ -6,7 +6,7 @@
 
 - **`vue-cli-service test:e2e`**
 
-  run e2e tests with [NightwatchJS](nightwatchjs.org).
+  run e2e tests with [NightwatchJS](http://nightwatchjs.org).
 
   Options:
 
