Bump actions/download-artifact from 7 to 8 (#531)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 7 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v7...v8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -306,7 +306,7 @@ jobs:
             help: "https://kind.sigs.k8s.io/docs/user/local-registry/"
         EOF
     - name: Download staged bundle
-      uses: actions/download-artifact@v7
+      uses: actions/download-artifact@v8
       with:
         name: servicebinding-runtime-bundle.tar
     - name: Relocate bundle
@@ -475,7 +475,7 @@ jobs:
         release_name: ${{ steps.get_version.outputs.VERSION }}
         draft: true
     - name: Download staged bundle
-      uses: actions/download-artifact@v7
+      uses: actions/download-artifact@v8
       with:
         name: servicebinding-runtime-bundle.tar
     - name: Upload servicebinding-runtime-bundle.tar