Bump pre-commit from 2.8.2 to 2.9.0 (#505)

Bumps [pre-commit](https://github.com/pre-commit/pre-commit) from 2.8.2 to 2.9.0.
- [Release notes](https://github.com/pre-commit/pre-commit/releases)
- [Changelog](https://github.com/pre-commit/pre-commit/blob/master/CHANGELOG.md)
- [Commits](pre-commit/pre-commit@v2.8.2...v2.9.0)

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

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

requirements/testing.txt

@@ -1,5 +1,5 @@
 -r production.txt
-pre-commit==2.8.2
+pre-commit==2.9.0
 isort==5.6.4
 coveralls==2.2.0
 flake8==3.8.4