Bump astral-sh/setup-uv from 3 to 6

Bumps [astral-sh/setup-uv](https://github.com/astral-sh/setup-uv) from 3 to 6.
- [Release notes](https://github.com/astral-sh/setup-uv/releases)
- [Commits](astral-sh/setup-uv@v3...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/test-libmaxminddb.yml

@@ -32,7 +32,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v6
 
       - name: Install tox
         run: uv tool install --python-preference only-managed --python 3.13 tox --with tox-uv --with tox-gh

.github/workflows/test.yml

@@ -23,7 +23,7 @@ jobs:
           submodules: true
           persist-credentials: false
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v6
       - name: Install tox
         run: uv tool install --python-preference only-managed --python 3.13 tox --with tox-uv --with tox-gh
       - name: Install Python