Build improvements (#569)

* Black linting

* Adding Black to dev dependencies and upping minimal python to 3.6.2 for compatibility

* Updating packages

* Removing pip-tools input and exporting requirements with poetry

* Deleting old setup files and test runner

* Trying 1.3.7

* Looser extras requirements to prevent conflicts

* Sorted imports with isort

* Added iSort to dev dependencies

* Fixes localtime for naive setups

django_q/brokers/__init__.py

@@ -1,7 +1,7 @@
 import importlib
 from typing import Optional
 
-from django.core.cache import caches, InvalidCacheBackendError
+from django.core.cache import InvalidCacheBackendError, caches
 
 from django_q.conf import Conf