Bump isort from 5.7.0 to 5.8.0 in /requirements (#809)

Bumps [isort](https://github.com/pycqa/isort) from 5.7.0 to 5.8.0.
- [Release notes](https://github.com/pycqa/isort/releases)
- [Changelog](https://github.com/PyCQA/isort/blob/develop/CHANGELOG.md)
- [Commits](PyCQA/isort@5.7.0...5.8.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements/lint.txt

@@ -1,3 +1,3 @@
 black==20.8.b1
 flake8==3.9.0
-isort==5.7.0
+isort==5.8.0