Remove release date from readme

Bumpversion cannot update the release date and trying to remember to
update it manually won't work.

README.rst

@@ -44,7 +44,7 @@ It works with Python 2.7, 3.3 and above, and supports MediaWiki 1.16 and above.
 For functions not available in the current MediaWiki, a ``MediaWikiVersionError`` is raised.
 
 The current stable `version 0.8.6 <https://github.com/mwclient/mwclient/archive/v0.8.6.zip>`_
-was released on 18 May 2017, and is `available through PyPI <https://pypi.python.org/pypi/mwclient>`_:
+is `available through PyPI <https://pypi.python.org/pypi/mwclient>`_:
 
 .. code-block:: console
 

setup.cfg

@@ -7,6 +7,8 @@ tag = True
 test = pytest
 
 [bumpversion:file:setup.py]
+search = version='{current_version}'
+replace = version='{new_version}'
 
 [bumpversion:file:mwclient/client.py]