Update link to Karma (#458)

The newest version is v1.0 but we shouldn't hard-code the path again.

Author: jehadassaf

src/guide/unit-testing.md

@@ -6,7 +6,7 @@ order: 22
 
 ## Setup and Tooling
 
-Anything compatible with a module-based build system will work, but if you're looking for a specific recommendation, try the [Karma](http://karma-runner.github.io/0.12/index.html) test runner. It has a lot of community plugins, including support for [Webpack](https://github.com/webpack/karma-webpack) and [Browserify](https://github.com/Nikku/karma-browserify). For detailed setup, please refer to each project's respective documentation, though these example Karma configurations for [Webpack](https://github.com/vuejs/vue-loader-example/blob/master/build/karma.conf.js) and [Browserify](https://github.com/vuejs/vueify-example/blob/master/karma.conf.js) may help you get started.
+Anything compatible with a module-based build system will work, but if you're looking for a specific recommendation, try the [Karma](http://karma-runner.github.io) test runner. It has a lot of community plugins, including support for [Webpack](https://github.com/webpack/karma-webpack) and [Browserify](https://github.com/Nikku/karma-browserify). For detailed setup, please refer to each project's respective documentation, though these example Karma configurations for [Webpack](https://github.com/vuejs/vue-loader-example/blob/master/build/karma.conf.js) and [Browserify](https://github.com/vuejs/vueify-example/blob/master/karma.conf.js) may help you get started.
 
 ## Simple Assertions