fix setup.cfg for zest.releaser

Author: PetrDlouhy

Diff for: setup.cfg

@@ -5,7 +5,7 @@ commit_args = --no-verify
 tag = True
 tag_name = {new_version}
 parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(\+\w+-(?P<dev>\d+))?
-serialize = 
+serialize =
 	{major}.{minor}.{patch}+{$BRANCH_NAME}-{dev}
 	{major}.{minor}.{patch}
 message = Version updated from {current_version} to {new_version}
@@ -19,7 +19,7 @@ long_description_content_type = text/markdown
 author = Corey Oordt
 author_email = [email protected]
 url = http://github.com/jazzband/django-categories
-classifiers = 
+classifiers =
 	Framework :: Django
 
 [options]
@@ -28,17 +28,17 @@ include_package_data = True
 packages = find:
 
 [options.packages.find]
-exclude = 
+exclude =
 	example*
 	docs
 	build
-include = 
+include =
 	categories
 	categories.*
 
 [flake8]
 ignore = D203,W503,E501
-exclude = 
+exclude =
 	.git
 	.tox
 	docs
@@ -65,3 +65,6 @@ search = Unreleased
 [bumpversion:file(diff link):CHANGELOG.md]
 search = {current_version}...HEAD
 replace = {current_version}...{new_version}
+
+[zest.releaser]
+python-file-with-version = categories/__init__.py