Bump dawidd6/action-download-artifact from 2 to 6 in /.github/workflows

Bumps [dawidd6/action-download-artifact](https://github.com/dawidd6/action-download-artifact) from 2 to 6.
- [Release notes](https://github.com/dawidd6/action-download-artifact/releases)
- [Commits](dawidd6/action-download-artifact@v2...v6)

---
updated-dependencies:
- dependency-name: dawidd6/action-download-artifact
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/preview-site.yml

@@ -15,7 +15,7 @@ jobs:
         uses: actions/checkout@master
 
       - name: Download Site dir
-        uses: dawidd6/action-download-artifact@v2
+        uses: dawidd6/action-download-artifact@v6
         with:
           github_token: ${{ secrets.GH_ACCESS_TOKEN }}
           workflow: build-and-preview-site.yml