Support not only .com

Following https://github.com/stevemao/get-pkg-repo/issues/9#issuecomment-264372893

Possible solution: in [`index.js`](https://github.com/repo-utils/parse-github-repo-url/blob/d81ad7298299fc82adac0ed8f710ee687dbb0d93/index.js#L12)
```js
// before
string = string.replace('.com:', '.com/')
// after
string = string.replace(/\.([A-Za-z]+)\:/, '.$1/');

```