fix(deps): Revert "fix: pin 'aoihttp < 3.7.0dev' (#634)" (#632) (#640)

This reverts commit 05f95246fab928fe2f445781117eeac8088497fb.

The compatibility bug was fixed in the aioresponses package version 0.7.1 - https://pypi.org/project/aioresponses/

Fixes #632 
diff --git a/system_tests/noxfile.py b/system_tests/noxfile.py
index 699a1b3..dcfe8ee 100644
--- a/system_tests/noxfile.py
+++ b/system_tests/noxfile.py
@@ -168,7 +168,7 @@
 
 # Test sesssions
 
-TEST_DEPENDENCIES_ASYNC = ["aiohttp < 3.7.0dev", "pytest-asyncio", "nest-asyncio"]
+TEST_DEPENDENCIES_ASYNC = ["aiohttp", "pytest-asyncio", "nest-asyncio"]
 TEST_DEPENDENCIES_SYNC = ["pytest", "requests"]
 PYTHON_VERSIONS_ASYNC = ["3.7"]
 PYTHON_VERSIONS_SYNC = ["2.7", "3.7"]