implements PEP440 in bumpversion

Author: Justin Kiggins

setup.cfg

@@ -1,7 +1,21 @@
 [bumpversion]
 current_version = 0.4.0
 commit = True
-tag = True
+tag = False
+parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(\.(?P<release>[a-z]+)(?P<n>\d+))?
+serialize =
+	{major}.{minor}.{patch}.{release}{n}
+	{major}.{minor}.{patch}
+
+[bumpversion:part:release]
+optional_value = gamma
+values =
+	a
+	b
+	rc
+	gamma
+
+[bumpversion:part:n]
 
 [bumpversion:file:visual_behavior/__init__.py]
 search = __version__ = "{current_version}"
@@ -22,4 +36,3 @@ exclude = git/*, notebooks/*, tests/*, scripts/*
 [coverage:run]
 omit = tests/*, visual_behavior/cohorts/*, visual_behavior/inscopix/*, scripts/*,
 	notebooks/*, circleci/*, .git/*, .tox/*, .cache/*, visual_behavior/pizza/*
-