I personally don't like this and I hope Github decides to revert these changes as it doesn't really fit the open spirit. However if you still want to search and

I personally don't like this and I hope Github decides to revert these changes as it doesn't really fit the open spirit. However if you still want to search and you're a duckduckgo user like me, simply use "bangs" in your url bar. e.g. !github some-repo