fix: upload and merge artifact naming conflict since action version v4

.github/actions/build/action.yaml

@@ -72,7 +72,7 @@ runs:
     - name: Upload digest
       uses: actions/upload-artifact@v4
       with:
-        name: digests
+        name: single-digest-${{ matrix.runs-on }}
         path: /tmp/digests/*
         if-no-files-found: error
         retention-days: 1

.github/actions/merge/action.yml

@@ -13,10 +13,12 @@ runs:
   using: "composite"
   steps:
     - name: Download digests
-      uses: actions/download-artifact@v3
+      uses: actions/upload-artifact/merge@v4
       with:
         name: digests
+        pattern: single-digest-*
         path: /tmp/digests
+        merge-multiple: true
 
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v3