Update dependency sphinxcontrib-qthelp to v2 (#35)

This PR contains the following updates:

| Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) |
|---|---|---|---|
| [sphinxcontrib-qthelp](https://redirect.github.com/sphinx-doc/sphinxcontrib-qthelp) ([changelog](https://redirect.github.com/sphinx-doc/sphinxcontrib-qthelp/blob/master/CHANGES.rst)) | `<=1.0.8` → `<=2.0.0` | ![age](https://developer.mend.io/api/mc/badges/age/pypi/sphinxcontrib-qthelp/2.0.0?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/sphinxcontrib-qthelp/1.0.8/2.0.0?slim=true) |

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### Release Notes

<details>
<summary>sphinx-doc/sphinxcontrib-qthelp (sphinxcontrib-qthelp)</summary>

### [`v2.0.0`](https://redirect.github.com/sphinx-doc/sphinxcontrib-qthelp/blob/HEAD/CHANGES.rst#Release-200-2024-07-28)

[Compare Source](https://redirect.github.com/sphinx-doc/sphinxcontrib-qthelp/compare/1.0.8...2.0.0)

\==========================

- Adopt Ruff
- Tighten MyPy settings
- Update GitHub actions versions

</details>

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Author: renovate[bot]

sphinx-plugin/pyproject.toml

@@ -34,7 +34,7 @@ dependencies = [
     "sphinxcontrib-devhelp<=2.0.0",
     "sphinxcontrib-htmlhelp<=2.1.0",
     "sphinxcontrib-serializinghtml<=2.0.0",
-    "sphinxcontrib-qthelp<=1.0.8",
+    "sphinxcontrib-qthelp<=2.0.0",
     "standard-imghdr; python_version >= '3.13'",
     "python-dispatch>=0.2.2",
     "importlib-metadata; python_version < '3.8'"