Update furo requirement from ~=2024.1.29 to ~=2024.5.6

Updates the requirements on [furo](https://github.com/pradyunsg/furo) to permit the latest version.
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2024.01.29...2024.05.06)

---
updated-dependencies:
- dependency-name: furo
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

pyproject.toml

@@ -125,7 +125,7 @@ typing = [
     "types-xmltodict ~= 0.13.0.2",
 ]
 docs = [
-    "furo ~= 2024.1.29",
+    "furo ~= 2024.5.6",
     "myst-parser ~= 3.0.0",
     # Sphinx 7.2.0 is the first version to drop Python 3.8.
     "sphinx >= 7.2.0",