Bump eslint from 8.19.0 to 8.23.1 in /backend

Bumps [eslint](https://github.com/eslint/eslint) from 8.19.0 to 8.23.1.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/main/CHANGELOG.md)
- [Commits](eslint/eslint@v8.19.0...v8.23.1)

---
updated-dependencies:
- dependency-name: eslint
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]