Remove python 3.6 support. (#718)

* Remove python 3.6 support.

* Remove unsupported code

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.6', '3.7', '3.8', '3.9']
+        python-version: ['3.7', '3.8', '3.9']
 
     steps:
     - uses: actions/checkout@v2

README.rst

@@ -31,7 +31,7 @@ UPDATE_ON_DUPLICATE_REG_ID: Transform create of an existing Device (based on reg
 
 Dependencies
 ------------
-- Python 3.6+
+- Python 3.7+
 - Django 2.2+
 - For the API module, Django REST Framework 3.7+ is required.
 - For WebPush (WP), pywebpush 1.3.0+ is required (optional). py-vapid 1.3.0+ is required for generating the WebPush private key; however this

setup.cfg

@@ -18,15 +18,14 @@ classifiers =
 	License :: OSI Approved :: MIT License
 	Programming Language :: Python
 	Programming Language :: Python :: 3
-	Programming Language :: Python :: 3.6
 	Programming Language :: Python :: 3.7
 	Programming Language :: Python :: 3.8
 	Programming Language :: Python :: 3.9
 	Topic :: Internet :: WWW/HTTP
 	Topic :: System :: Networking
 
 [options]
-python_requires = >= 3.6
+python_requires = >= 3.7
 packages = find:
 install_requires =
 	Django>=2.2

tests/test_admin.py

@@ -126,12 +126,7 @@ def test_send_bulk_messages_action_fail(self):
 			self.assertEqual(message.token, "abc")
 			self.assertEqual(message.android.notification.body, "Test bulk notification")
 
-			# 3.6 adds a `,` to the string representation of the exception
-			python_version = sys.version_info[:2]
-			if python_version >= (3, 7):
-				error_message = "Some messages could not be processed: UnregisteredError('error')"
-			else:
-				error_message = "Some messages could not be processed: UnregisteredError('error',)"
+			error_message = "Some messages could not be processed: UnregisteredError('error')"
 
 			admin.message_user.assert_called_once_with(
 				request, error_message, level=messages.ERROR

tox.ini

@@ -2,13 +2,12 @@
 skipsdist = False
 usedevelop = true
 envlist =
-    py{36,37,38,39}-dj{22,32}
+    py{37,38,39}-dj{22,32}
     py{38,39}-dj{40,405}
     flake8
 
 [gh-actions]
 python =
-    3.6: py36
     3.7: py37
     3.8: py38
     3.9: py39, flake8