Check aioredis version for deprecated parameter

Starting with aioredis 1.3.1, the loop parameter is deprecated when calling
create_redis. See aio-libs-abandoned/aioredis-py#666 and django/channels_redis#179.

When running Python 3.8+ and aioredis 1.3.1+, calls should omit the loop
parameter. Otherwise, continue to include the parameter for the older
versions that expect it.

channels_redis/core.py

@@ -7,6 +7,7 @@
 import logging
 import random
 import string
+import sys
 import time
 import types
 
@@ -18,6 +19,8 @@
 
 logger = logging.getLogger(__name__)
 
+AIOREDIS_VERSION = tuple(map(int, aioredis.__version__.split(".")))
+
 
 def _wrap_close(loop, pool):
     """
@@ -70,7 +73,11 @@ async def pop(self, loop=None):
         """
         conns, loop = self._ensure_loop(loop)
         if not conns:
-            conns.append(await aioredis.create_redis(**self.host, loop=loop))
+            if sys.version_info >= (3, 8, 0) and AIOREDIS_VERSION >= (1, 3, 1):
+                conn = await aioredis.create_redis(**self.host)
+            else:
+                conn = await aioredis.create_redis(**self.host, loop=loop)
+            conns.append(conn)
         conn = conns.pop()
         if conn.closed:
             conn = await self.pop(loop=loop)