I've got a request in bug #1347384 for building python3x-elasticsearch for epel7. This depends on python3x-urllib3 which is not in epel. RHEL ships urllib3 for python2. If I understand the python3 epel situation correctly this would mean we need to create a new review request for an epel only pyhon3-urllib3 package. Are you willing to create this?
There is now actually a python36-urllib3 available. :) Enjoy!