Update Readme to note the active fork

Hi,
You're still ranking pretty highly in Google searches for pyquery. Would you mind updating your readme to note that https://github.com/gawel/pyquery/ is an active fork (the active fork? It's the one in pip)

[elebumm]

I was wondering if this package was still maintained because of this being the first github result when I google PyQuery. It's been 7 years since the last commit and this issue is 3 and a half years old. Perhaps giving the maintainer an email will remind him?