build(deps-dev): bump eslint-plugin-testing-library from 7.5.2 to 7.6.8

Bumps [eslint-plugin-testing-library](https://github.com/testing-library/eslint-plugin-testing-library) from 7.5.2 to 7.6.8.
- [Release notes](https://github.com/testing-library/eslint-plugin-testing-library/releases)
- [Changelog](https://github.com/testing-library/eslint-plugin-testing-library/blob/main/.releaserc.json)
- [Commits](testing-library/eslint-plugin-testing-library@v7.5.2...v7.6.8)

---
updated-dependencies:
- dependency-name: eslint-plugin-testing-library
  dependency-version: 7.6.8
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]