Bump multidict from 4.7.6 to 5.2.0 (#627)

Bumps [multidict](https://github.com/aio-libs/multidict) from 4.7.6 to 5.2.0.
- [Release notes](https://github.com/aio-libs/multidict/releases)
- [Changelog](https://github.com/aio-libs/multidict/blob/master/CHANGES.rst)
- [Commits](aio-libs/multidict@v4.7.6...v5.2.0)

---
updated-dependencies:
- dependency-name: multidict
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

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

Author: dependabot[bot]

requirements-dev.txt

@@ -17,7 +17,7 @@ pytest-cov==3.0.0
 pytest-mock==3.6.1
 pytest-sugar==0.9.4
 aiohttp<3.9
-multidict==4.7.6
+multidict==5.2.0
 chardet==3.0.4
 yarl==1.7.2
 aiomcache==0.6.0