Update aiohttp requirement from <3.8.0,>=3.6.0 to >=3.6.0,<3.9.0 (#19)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -1 +1 @@
-aiohttp>=3.6.0,<3.8.0
+aiohttp>=3.6.0,<3.9.0