[setup.py] use bump2version, up-to-date fork of bumpversion

The latter is no longer maintained.

https://github.com/c4urself/bump2version

dev-requirements.txt

@@ -1,4 +1,4 @@
 pytest>=3.0
 tox>=2.5
-bumpversion>=0.5.3
-sphinx>=1.5.5
+bump2version>=0.5.6
+sphinx>=1.5.5

setup.py

@@ -28,7 +28,7 @@ pytest_runner = ['pytest_runner'] if needs_pytest else []
 needs_wheel = {'bdist_wheel'}.intersection(sys.argv)
 wheel = ['wheel'] if needs_wheel else []
 needs_bumpversion = {'release'}.intersection(sys.argv)
-bumpversion = ['bumpversion'] if needs_bumpversion else []
+bumpversion = ['bump2version'] if needs_bumpversion else []
 
 # Trove classifiers for PyPI
 classifiers = {"classifiers": [
@@ -104,7 +104,7 @@ class release(Command):
 	Links:
 	- http://semver.org/
 	- https://www.python.org/dev/peps/pep-0440/
-	- https://github.com/peritus/bumpversion
+	- https://github.com/c4urself/bump2version
 	"""
 
 	description = "update version strings for release"