Bump pre-commit from 2.4.0 to 2.6.0 in /src/requirements (#567)

Bumps [pre-commit](https://github.com/pre-commit/pre-commit) from 2.4.0 to 2.6.0.
- [Release notes](https://github.com/pre-commit/pre-commit/releases)
- [Changelog](https://github.com/pre-commit/pre-commit/blob/master/CHANGELOG.md)
- [Commits](https://github.com/pre-commit/pre-commit/compare/v2.4.0...v2.6.0)

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

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

src/requirements/dev.txt

@@ -5,7 +5,7 @@ factory_boy==2.12.0
 coverage==5.1
 codecov==2.1.4
 black==19.10b0
-pre-commit==2.4.0
+pre-commit==2.6.0
 isort==4.3.21
 hypothesis==5.16.0
 flake8==3.8.2