Bump pytest-cov from 5.0.0 to 6.0.0 in /src (#4041)

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 5.0.0 to 6.0.0.
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v5.0.0...v6.0.0)

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

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

Author: dependabot[bot]

src/requirements.txt

@@ -3,7 +3,7 @@ flask-talisman==1.1.0
 gunicorn==22.0.0
 pytest==8.2.2
 pytest-watch==4.2.0
-pytest-cov==5.0.0
+pytest-cov==6.0.0
 sqlfluff==3.3.0
 
 # sql/util/* dependencies