⬆️ Update pytest-cov requirement from >=4,<6 to >=4,<7

Updates the requirements on [pytest-cov](https://github.com/pytest-dev/pytest-cov) to permit the latest version.
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v4.0.0...v6.0.0)

---
updated-dependencies:
- dependency-name: pytest-cov
  dependency-type: direct:development
...

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

pyproject.toml

@@ -49,7 +49,7 @@ hypothesis = "^6.124.1"
 pyupgrade = "^3.19.1"
 safety = ">=2.3.5,<4.0.0"
 pytest-html = "^3.2.0"
-pytest-cov = ">=4,<6"
+pytest-cov = ">=4,<7"
 Sphinx = ">=5.3,<8.0"
 sphinxcontrib-applehelp = "^1.0.8"
 sphinxcontrib-devhelp = "^1.0.6"