Update sphinx-autoapi requirement from >=3.6.0 to >=3.8.0 (#229)

Updates the requirements on [sphinx-autoapi](https://github.com/readthedocs/sphinx-autoapi) to permit the latest version.
- [Release notes](https://github.com/readthedocs/sphinx-autoapi/releases)
- [Changelog](https://github.com/readthedocs/sphinx-autoapi/blob/main/CHANGELOG.rst)
- [Commits](readthedocs/sphinx-autoapi@v3.6.0...v3.8.0)

---
updated-dependencies:
- dependency-name: sphinx-autoapi
  dependency-version: 3.8.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

pyproject.toml

@@ -72,7 +72,7 @@ changelog = [
 docs = [
     "pydata-sphinx-theme>=0.16.1",
     "sphinx>=8.2.3",
-    "sphinx-autoapi>=3.6.0",
+    "sphinx-autoapi>=3.8.0",
     "sphinx-autodoc-typehints>=3.2.0",
     "sphinx-click>=6.0.0",
     "sphinx-copybutton>=0.5.2",