Bump aiohttp from 3.8.0 to 3.8.1 (#650)

Bumps [aiohttp](https://github.com/aio-libs/aiohttp) from 3.8.0 to 3.8.1.
- [Release notes](https://github.com/aio-libs/aiohttp/releases)
- [Changelog](https://github.com/aio-libs/aiohttp/blob/master/CHANGES.rst)
- [Commits](aio-libs/aiohttp@v3.8.0...v3.8.1)

---
updated-dependencies:
- dependency-name: aiohttp
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

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

requirements/ci.txt

@@ -1,6 +1,6 @@
 codecov==2.1.12
 tox==3.24.4
 tox-travis==0.12
-aiohttp==3.8.0
+aiohttp==3.8.1
 yarl==1.7.2
 multidict==5.2.0