Restored commit tag check

Author: arjanz

setup.py

@@ -42,8 +42,7 @@
 
     version = environ['GITHUB_REF'].replace('refs/tags/v', '')
 else:
-    # raise ValueError('Missing commit tag, can\'t set version')
-    version = '1.0.0-dev1'
+    raise ValueError('Missing commit tag, can\'t set version')
 
 here = path.abspath(path.dirname(__file__))