Update aiohttp requirement from ~=3.8.6 to ~=3.9.1

Updates the requirements on [aiohttp](https://github.com/aio-libs/aiohttp) to permit the latest version.
- [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...v3.9.1)

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

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

requirements.txt

@@ -1,4 +1,4 @@
-aiohttp~=3.8.6
+aiohttp~=3.9.1
 colorama~=0.4.6
 discord~=2.3.2
 dpytest~=0.7.0