Bump isort from 5.9.3 to 5.10.1

Bumps [isort](https://github.com/pycqa/isort) from 5.9.3 to 5.10.1.
- [Release notes](https://github.com/pycqa/isort/releases)
- [Changelog](https://github.com/PyCQA/isort/blob/main/CHANGELOG.md)
- [Commits](PyCQA/isort@5.9.3...5.10.1)

---
updated-dependencies:
- dependency-name: isort
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements/testing.txt

@@ -1,5 +1,5 @@
 -r production.txt
-isort==5.9.3
+isort==5.10.1
 coveralls==3.2.0
 flake8==3.9.2
 flake8-isort==4.0.0