Bump isort from 5.9.2 to 5.9.3 (#611)

Bumps [isort](https://github.com/pycqa/isort) from 5.9.2 to 5.9.3.
- [Release notes](https://github.com/pycqa/isort/releases)
- [Changelog](https://github.com/PyCQA/isort/blob/main/CHANGELOG.md)
- [Commits](PyCQA/isort@5.9.2...5.9.3)

---
updated-dependencies:
- dependency-name: isort
  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/test.txt

@@ -5,5 +5,5 @@ pytest-asyncio==0.16.0
 flake8==3.9.2
 mypy==0.910
 black==21.9b0
-isort==5.9.2
+isort==5.9.3
 -r ci.txt