Deprecate Python 3.6 support, add Python 3.10

* Deprecate Python 3.6 and remove code to support Python versions < 3.7.
* Add Python 3.10 to tox configuration.

channels_redis/pubsub.py

@@ -1,7 +1,6 @@
 import asyncio
 import functools
 import logging
-import sys
 import types
 import uuid
 
@@ -13,12 +12,6 @@
 logger = logging.getLogger(__name__)
 
 
-if sys.version_info >= (3, 7):
-    get_running_loop = asyncio.get_running_loop
-else:
-    get_running_loop = asyncio.get_event_loop
-
-
 def _wrap_close(proxy, loop):
     original_impl = loop.close
 
@@ -67,7 +60,7 @@ def deserialize(self, message):
         return msgpack.unpackb(message)
 
     def _get_layer(self):
-        loop = get_running_loop()
+        loop = asyncio.get_running_loop()
 
         try:
             layer = self._layers[loop]

setup.py

@@ -29,7 +29,7 @@
     zip_safe=False,
     packages=find_packages(exclude=["tests"]),
     include_package_data=True,
-    python_requires=">=3.6",
+    python_requires=">=3.7",
     install_requires=[
         "aioredis~=1.0",
         "msgpack~=1.0",

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{36,37,38,39}
+    py{37,38,39,310}
     qa
 
 [testenv]