Bump aiohttp from 3.7.4 to 3.7.4.post0

Bumps [aiohttp](https://github.com/aio-libs/aiohttp) from 3.7.4 to 3.7.4.post0.
- [Release notes](https://github.com/aio-libs/aiohttp/releases)
- [Changelog](https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst)
- [Commits](https://github.com/aio-libs/aiohttp/compare/v3.7.4...v3.7.4.post0)

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -4,7 +4,7 @@ pandas==1.2.3
 ccxt==1.42.66
 # Pin cryptography for now due to rust build errors with piwheels
 cryptography==3.4.6
-aiohttp==3.7.4
+aiohttp==3.7.4.post0
 SQLAlchemy==1.3.23
 python-telegram-bot==13.3
 arrow==1.0.3