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/wheel.yaml

@@ -69,11 +69,11 @@ jobs:
     needs: [build_wheels, build_sdist]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v6
         with:
           name: sdist
           path: dist
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v6
         with:
           pattern: wheels-*
           path: dist
@@ -89,11 +89,11 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/v')
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v6
         with:
           name: sdist
           path: dist
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v6
         with:
           pattern: wheels-*
           path: dist
@@ -110,7 +110,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch'
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v6
         with:
           pattern: wheels-*
           path: dist