Bump pytest-cov from 6.2.1 to 7.0.0 in /back-end

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 6.2.1 to 7.0.0.
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v6.2.1...v7.0.0)

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

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

Author: dependabot[bot]

back-end/requirements.txt

@@ -16,7 +16,7 @@ starlette==0.47.3
 typing_extensions==4.15.0
 uvicorn==0.35.0
 pytest==8.4.1
-pytest-cov==6.2.1
+pytest-cov==7.0.0
 mysql-connector==2.2.9
 mysql-connector-python==9.4.0
 ddt==1.7.2