Bump aiohttp from 3.6.2 to 3.7.4

Bumps [aiohttp](https://github.com/aio-libs/aiohttp) from 3.6.2 to 3.7.4.
- [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/v3.6.2...v3.7.4)

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

requirements.txt

@@ -1,5 +1,5 @@
 aiofiles==0.5.0
-aiohttp==3.6.2
+aiohttp==3.7.4
 aiomysql==0.0.20
 Animapy==1.5.3.1
 appdirs==1.4.4