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/signals.py

@@ -1,7 +1,7 @@
 import importlib
 
 from django.db.models.signals import post_save
-from django.dispatch import receiver, Signal
+from django.dispatch import Signal, receiver
 from django.utils.translation import gettext_lazy as _
 
 from django_q.conf import logger
@@ -31,6 +31,7 @@ def call_hook(sender, instance, **kwargs):
                 )
             )
 
+
 # args: task
 pre_enqueue = Signal()