chore(deps-dev): bump aiohttp from 3.8.6 to 3.9.0

Bumps [aiohttp](https://github.com/aio-libs/aiohttp) from 3.8.6 to 3.9.0.
- [Release notes](https://github.com/aio-libs/aiohttp/releases)
- [Changelog](https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst)
- [Commits](aio-libs/aiohttp@v3.8.6...v3.9.0)

---
updated-dependencies:
- dependency-name: aiohttp
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements.dev.txt

@@ -1,4 +1,4 @@
-aiohttp==3.8.6
+aiohttp==3.9.0
 black>=20.8b1
 bump2version==1.0.1
 covidcast==0.1.5