chore(deps-dev): bump isort from 4.3.21 to 5.0.4 (#7117)

Bumps [isort](https://github.com/timothycrosley/isort) from 4.3.21 to 5.0.4.
- [Release notes](https://github.com/timothycrosley/isort/releases)
- [Changelog](https://github.com/timothycrosley/isort/blob/develop/CHANGELOG.md)
- [Commits](PyCQA/isort@4.3.21...5.0.4)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

requirements/dev.txt

@@ -3,7 +3,7 @@
 nose==1.3.7
 pylint==2.5.3
 pep8==1.7.1
-isort==4.3.21
+isort==5.0.4
 black==19.10b0
 pre-commit==2.6.0
 pytype==2020.6.26