github-actions: bump actions/download-artifact from 4 to 8 (#608)

Author: dependabot[bot]

.github/workflows/docker-riverproui.yaml

@@ -170,7 +170,7 @@ jobs:
         uses: aws-actions/amazon-ecr-login@v2
 
       - name: Download digests
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v8
         with:
           path: /tmp/digests
           pattern: pro-digests-*

.github/workflows/docker-riverui.yaml

@@ -122,7 +122,7 @@ jobs:
 
     steps:
       - name: Download digests
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v8
         with:
           path: /tmp/digests
           pattern: digests-*