pip(deps-dev): bump pytest-cov from 6.1.1 to 7.0.0 in /backend (#122)

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 6.1.1 to 7.0.0.
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v6.1.1...v7.0.0)

---
updated-dependencies:
- dependency-name: pytest-cov
  dependency-version: 7.0.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

backend/requirements-dev.txt

@@ -1,5 +1,5 @@
 # Testing
-pytest-cov==6.1.1
+pytest-cov==7.0.0
 pytest==8.4.2
 pytest-asyncio==1.2.0
 httpx==0.28.1