ci(workflows): enhance artifact upload and download processes

- Streamlined artifact uploads by adding specific upload tasks for 'artifacthub' alongside the previous 'helm' artifact.
- Introduced a download step for 'artifacthub' artifacts to ensure proper retrieval in subsequent jobs.

Author: winromulus

.github/workflows/main.yaml

@@ -40,10 +40,13 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: helm
-          path: |
-            .artifacts/helm
-            src/helm/artifacthub-repo.yaml
+          path: .artifacts/helm
 
+      - name: "artifacts - upload - artifacthub"
+        uses: actions/upload-artifact@v4
+        with:
+          name: artifacthub
+          path: src/helm/artifacthub-repo.yaml
 
       - name: "artifacts - upload - kubectl manifests"
         uses: actions/upload-artifact@v4
@@ -105,6 +108,12 @@ jobs:
           name: helm
           path: .artifacts/helm
 
+      - name: artifacts - download - artifacthub
+        uses: actions/download-artifact@v4
+        with:
+          name: artifacthub
+          path: .artifacts/artifacthub
+
       - name: artifacts - download - kubectl manifests
         uses: actions/download-artifact@v4
         with: