build(deps): bump actions/download-artifact from 4 to 6

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4...v6)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  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/python-wheels-test.yml

@@ -31,7 +31,7 @@ jobs:
           python-version: '3.12' 
 
       - name: Download the wheels
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v6
         with:
           path: dist/
           pattern: python-wheels-${{runner.os}}_${{inputs.arch}}*

.github/workflows/python-wheels.yml

@@ -144,7 +144,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v6
         with:
           path: dist/
           pattern: python-wheels-*