bump version 0.5.3 -> 0.6.0

Author: mbarkhau

setup.py

@@ -25,7 +25,7 @@ def finalize_options(self):
 
 setup(
     name='cmarkgfm',
-    version='0.5.3',
+    version='0.6.0',
     description="Minimal bindings to GitHub's fork of cmark",
     long_description=long_description,
     long_description_content_type="text/x-rst",