Normalize GitHub urls

[sindresorhus]

Server should have some custom logic for GitHub to normalize urls to prevent duplicates and return consistent urls.

All these are valid GitHub clone urls:

git://github.com/sakabako/scrollMonitor.git
git://github.com/sakabako/scrollMonitor
https://github.com/sakabako/scrollMonitor.git
https://github.com/sakabako/scrollMonitor
git@github.com:sakabako/scrollMonitor.git
git@github.com:sakabako/scrollMonitor # not sure about this

They should be saved to one format.

[satazor]

I've made similar normalisation in the rewrite.

Trailing slashes should also be normalised:

git://github.com/sakabako/scrollMonitor.git/ -> git://github.com/sakabako/scrollMonitor.git
git://github.com/sakabako/scrollMonitor/ -> git://github.com/sakabako/scrollMonitor.git