Exempt GitHub.com from the global rules

👋 I work at GitHub where we were getting reports of certain requests failing. We eventually tracked it down to this extension 😄 It turns out we had a query param called ref (the reference/branch name) which was getting stripped by ClearURLs.

We're working around it on our side by renaming the param, but as you might imagine given the business we're in, it's entirely possible we might want to name a param ref again in the future 🙈

So given that GitHub.com doesn't do any 3rd party tracking I'd like to propose excluding it from the global rules.