chore(github-deps): bump astral-sh/setup-uv from 5 to 6

Bumps [astral-sh/setup-uv](https://github.com/astral-sh/setup-uv) from 5 to 6.
- [Release notes](https://github.com/astral-sh/setup-uv/releases)
- [Commits](https://github.com/astral-sh/setup-uv/compare/v5...v6)

---
updated-dependencies:
- dependency-name: astral-sh/setup-uv
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/update-readthedocs.yml

@@ -41,7 +41,7 @@ jobs:
           python-version: '3.11'
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@0c5e2b8115b80b4c7c5ddf6ffdd634974642d182 # v5.4.1
+        uses: astral-sh/setup-uv@9a311713f4acad0acceb25fb016307e47c3887b6 # v5.4.1
 
       - name: Sync with uv
         run: uv sync --extra docs