fix regex

.bumpversion.cfg

@@ -2,17 +2,15 @@
 current_version = 0.0.1-dev
 commit = True
 tag = True
-parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(\-(?P<release>[a-z]+))?
+parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(?:(?P<release>[a-z]+))?
 serialize = 
 	{major}.{minor}.{patch}-{release}
 	{major}.{minor}.{patch}
 
 [bumpversion:file:src/polyphy/_version.py]
 
 [bumpversion:file:setup.py]
-
-[commit]
-message = Bump version: {current_version} → {new_version}
+message = Bump version: {new_version}
 
 [bumpversion:part:release]
 optional_value = gamma