Bump isort from 5.9.1 to 5.9.3

Bumps [isort](https://github.com/pycqa/isort) from 5.9.1 to 5.9.3.
- [Release notes](https://github.com/pycqa/isort/releases)
- [Changelog](https://github.com/PyCQA/isort/blob/main/CHANGELOG.md)
- [Commits](https://github.com/pycqa/isort/compare/5.9.1...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>

requirements.txt

 # Linting
 flake8==3.9.2
 flake8-debugger==4.0.0
-isort==5.9.1
+isort==5.9.3
 
 # Helpers
 pyprof2calltree>=1.4,<1.5