Bump pre-commit from 2.5.1 to 2.6.0 (#459)

Author: dependabot[bot]

requirements/requirements_dev.txt

@@ -8,7 +8,7 @@ flake8-bandit==2.1.2
 flake8-bugbear==20.1.4
 hypothesis==4.53.1
 placebo==0.9.0
-pre-commit==2.5.1
+pre-commit==2.6.0
 pylint==2.5.3
 pytest==5.4.3
 pytest-black==0.3.9