Bump isort from 5.2.2 to 5.4.2

Bumps [isort](https://github.com/timothycrosley/isort) from 5.2.2 to 5.4.2.
- [Release notes](https://github.com/timothycrosley/isort/releases)
- [Changelog](https://github.com/timothycrosley/isort/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/timothycrosley/isort/compare/5.2.2...5.4.2)

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

requirements.txt

 flake8==3.8.3
 flake8-debugger==3.2.1
 flake8-blind-except==0.1.1
-isort==5.2.2
+isort==5.4.2
 
 # Helpers
 pyprof2calltree==1.4.5