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](astral-sh/setup-uv@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>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -51,7 +51,7 @@ jobs:
           python-version: ${{ matrix.python-version }}
 
       - name: Set up uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v6
         with:
           cache-dependency-glob: |
             pyproject.toml
@@ -115,7 +115,7 @@ jobs:
         with:
           python-version: '3.13'
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v6
       - name: Set up project tools
         run: uv pip install poethepoet