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/tests/testing_utilities/multiple_database_routers.py

@@ -25,14 +25,14 @@ class TestingMultipleAppsDatabaseRouter:
 
     @staticmethod
     def is_admin(model):
-        return model._meta.app_label in ['admin']
+        return model._meta.app_label in ["admin"]
 
     def db_for_read(self, model, **hints):
         if self.is_admin(model):
-            return 'admin'
-        return 'default'
+            return "admin"
+        return "default"
 
     def db_for_write(self, model, **hints):
         if self.is_admin(model):
-            return 'admin'
-        return 'default'
+            return "admin"
+        return "default"