title: ModuleNotFoundError: importlib when pushing to Heroku despite local changes
body: <p>I get this error when I try to push to Heroku, the traceback is: <code>"/app/.heroku/python/lib/pytho                                                                                                                                                 n3.7/site-packages/appconf/utils.py", line 5, in import_attribute
  2018-12-18T16:39:08.833497+00:00 app[web.1]: from django.utils.importlib import                                                                                                                                                  import_module
  </code></p>
  
  <p>That path doesn't exist on my computer so I assume it's Heroku's own file, but I do have that same file and almost same path in my computer (it's in the directory that's linked to the remote repo. So I went to <code>utils.py</code> and commented out the line <code>django.utils.importlib import                                                                                                                              import_module</code> and replaced it from <code>from importlib import import_module</code> which I've learned is compatible with Python 3. </p>
  
  <p>However I still receive the same error when pushing, because that file isn't updated on Heroku. How would I go about fixing that library?</p>