build(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](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

@@ -15,7 +15,7 @@ jobs:
           persist-credentials: false
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v6
         with:
           enable-cache: true
           cache-dependency-glob: cookiecutter.json

.github/workflows/zizmor.yml

@@ -22,7 +22,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@v6
 
       - name: Run zizmor 🌈
         # Run it for both this repo and the templated cookiecutter repo.