Update dependency pytest-cov to v6 (#466)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [pytest-cov](https://redirect.github.com/pytest-dev/pytest-cov)
([changelog](https://pytest-cov.readthedocs.io/en/latest/changelog.html))
| `==5.0.0` -> `==6.0.0` |
[![age](https://developer.mend.io/api/mc/badges/age/pypi/pytest-cov/6.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![adoption](https://developer.mend.io/api/mc/badges/adoption/pypi/pytest-cov/6.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![passing](https://developer.mend.io/api/mc/badges/compatibility/pypi/pytest-cov/5.0.0/6.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pytest-cov/5.0.0/6.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Release Notes

<details>
<summary>pytest-dev/pytest-cov (pytest-cov)</summary>

###
[`v6.0.0`](https://redirect.github.com/pytest-dev/pytest-cov/blob/HEAD/CHANGELOG.rst#600-2024-10-29)

[Compare
Source](https://redirect.github.com/pytest-dev/pytest-cov/compare/v5.0.0...v6.0.0)

- Updated various documentation inaccuracies, especially on subprocess
handling.
- Changed fail under checks to use the precision set in the coverage
configuration.
    Now it will perform the check just like `coverage report` would.
- Added a `--cov-precision` cli option that can override the value set
in your coverage configuration.
-   Dropped support for now EOL Python 3.8.

</details>

---

### Configuration

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are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
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---

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requirements_dev.txt

@@ -5,7 +5,7 @@ mypy==1.13.0
 pdoc==15.0.0
 pip==24.3.1
 pre-commit==4.0.1
-pytest-cov==5.0.0
+pytest-cov==6.0.0
 pytest==8.3.3
 ruff==0.7.1