build(deps-dev): bump pre-commit from 2.7.1 to 2.8.2 in /backend

Bumps [pre-commit](https://github.com/pre-commit/pre-commit) from 2.7.1 to 2.8.2.
- [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@v2.7.1...v2.8.2)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

backend/requirements-dev.txt

@@ -1,5 +1,5 @@
 fakeredis==1.4.4
-pre-commit==2.7.1
+pre-commit==2.8.2
 pytest==6.1.1
 pytest-responses==0.4.0
 responses==0.12.0