doc(README): remove issue stats

They do not get updated for some reason, generally the
site is not quite production ready it seems, or is by
now overwhelmed.

[skip ci]

Author: Byron

README.md

@@ -101,8 +101,6 @@ New BSD License.  See the LICENSE file.
 [![Build Status](https://travis-ci.org/gitpython-developers/GitPython.svg)](https://travis-ci.org/gitpython-developers/GitPython)
 [![Code Climate](https://codeclimate.com/github/gitpython-developers/GitPython/badges/gpa.svg)](https://codeclimate.com/github/gitpython-developers/GitPython)
 [![Documentation Status](https://readthedocs.org/projects/gitpython/badge/?version=stable)](https://readthedocs.org/projects/gitpython/?badge=stable)
-[![Issue Stats](http://www.issuestats.com/github/gitpython-developers/GitPython/badge/pr)](http://www.issuestats.com/github/gitpython-developers/GitPython)
-[![Issue Stats](http://www.issuestats.com/github/gitpython-developers/GitPython/badge/issue)](http://www.issuestats.com/github/gitpython-developers/GitPython)
 
 Now that there seems to be a massive user base, this should be motivation enough to let git-python return to a proper state, which means
 
@@ -111,4 +109,4 @@ Now that there seems to be a massive user base, this should be motivation enough
 
 [twitch-channel]: http://www.twitch.tv/byronimo/profile
 [youtube-playlist]: https://www.youtube.com/playlist?list=PLMHbQxe1e9MnoEcLhn6Yhv5KAvpWkJbL0
-[contributing]: https://github.com/gitpython-developers/GitPython/blob/master/README.md
+[contributing]: https://github.com/gitpython-developers/GitPython/blob/master/README.md