Bump aiohttp from 3.4.4 to 3.7.4

Bumps [aiohttp](https://github.com/aio-libs/aiohttp) from 3.4.4 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](aio-libs/aiohttp@v3.4.4...v3.7.4)

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

requirements.txt

@@ -1,3 +1,3 @@
 pytz
-aiohttp==3.4.4
+aiohttp==3.7.4
 python-slugify==1.2.6