Bump aiohttp pin to support Python 3.10

Author: hugovk

tox.ini

@@ -21,7 +21,7 @@ extras =
     py{36,37,38,39,310}: async
 deps =
     py{36,37,38,39,310}: aioresponses==0.5.0
-    py{36,37,38,39,310}: aiohttp==3.4.4
+    py{36,37,38,39,310}: aiohttp==3.7.4
     py{36,37,38,39,310}: pytest-asyncio==0.11.0
 commands = coverage run --parallel -m pytest {posargs}