www/py-aiohttp: update to 3.8.1 release (+)

Force update due to devel/py-async_timeout update which
prevent build of py-azure-mgmt and py-certbot frameworks.

Changelog: https://github.com/aio-libs/aiohttp/releases/tag/v3.8.0b0

		https://github.com/aio-libs/aiohttp/releases/tag/v3.8.1

With hat: ports-secteam