Bump isort from 5.5.3 to 5.5.4 in /requirements (#15596)
Bump isort from 5.5.3 to 5.5.4 in /requirements (#15596)

Bumps [isort](https://github.com/pycqa/isort) from 5.5.3 to 5.5.4.
- [Release notes](https://github.com/pycqa/isort/releases)
- [Changelog](https://github.com/PyCQA/isort/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/pycqa/isort/compare/5.5.3...5.5.4)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
eviljeff/olympia,bqbn/addons-server,wagnerand/addons-server,mozilla/addons-server,mozilla/olympia,bqbn/addons-server,eviljeff/olympia,wagnerand/addons-server,mozilla/olympia,bqbn/addons-server,mozilla/olympia,diox/olympia,mozilla/addons-server,wagnerand/addons-server,mozilla/addons-server,diox/olympia,bqbn/addons-server,mozilla/olympia,mozilla/addons-server,diox/olympia,wagnerand/addons-server,diox/olympia,eviljeff/olympia,eviljeff/olympia