Improve GitHub detection in resolverFactory.js

As per @satazor's issue [https://github.com/bower/bower/issues/737] improved detection of GitHub [`git://github.com`] URLs by <del>using `mout` to capture the string rather than a regex test. `mout` is used in this capacity elsewhere is codebase, so continuing pattern.</del> making the regex detect both sides of `github.com` reliably.