The bitbucket website will allow you to track your revisions, and allow users like myself to make patches against your code. You can then pull those patches in and add them to your code.
Bitbucket uses Mercurial, which is an amazing Revision control system. I suggest you check it out, and you'll never use anything else to monitor your code changes again! Just read http://hginit.com/ for a quick startup, and you can even get a copy of your plugin into Bitbucket as soon as you want for free!
...but yes you want to keep your "published" version here on WordPress, but you can do all your updates, fixes, and revision control through Mercurial and Bitbucket.