Allow beta and release candidates

Author: mvantellingen

.bumpversion.cfg

@@ -4,6 +4,21 @@ commit = True
 tag = True
 tag_name = {new_version}
 
+parse = ^
+    (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)  # minimum major.minor.patch, 1.2.3
+    (?:
+        (?P<prerel>b|rc)  # pre-release segment
+        (?P<prerelversion>\d+)  # pre-release version num
+    )?
+serialize =
+    {major}.{minor}.{patch}{prerel}{prerelversion}
+    {major}.{minor}.{patch}
+
+[bumpversion:part:prerel]
+values =
+    b
+    rc
+
 [bumpversion:file:setup.py]
 
 [bumpversion:file:docs/conf.py]