Bump aiohttp from 3.8.5 to 3.9.0 in /app/backend (#24)

Bumps [aiohttp](https://github.com/aio-libs/aiohttp) from 3.8.5 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@v3.8.5...v3.9.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

app/backend/requirements.txt

@@ -3,4 +3,4 @@ azure-search-documents==11.4.0b6
 quart==0.19.3
 openai[datalib]==0.27.8
 uvicorn[standard]==0.23.2
-aiohttp==3.8.5
+aiohttp==3.9.0