apply-tags: Tag multi-arch images as expected

When copying an image manifest, skopeo by default only copies
the image matching the architecture of the system running skopeo. It
does not copy the image manifest as expected.

In my testing, adding the --multi-arch all flag on single architecture images
works without error.

task/apply-tags/0.1/apply-tags.yaml

@@ -47,7 +47,7 @@ spec:
           IMAGE_WITHOUT_TAG=$(echo "$IMAGE" | sed 's/:[^:]*$//')
           for tag in "$@"; do
             echo "Applying tag $tag"
-            skopeo copy docker://$IMAGE docker://$IMAGE_WITHOUT_TAG:$tag
+            skopeo copy --multi-arch all docker://"$IMAGE" docker://"$IMAGE_WITHOUT_TAG:$tag"
           done
         else
           echo "No additional tags parameter specified"
@@ -70,7 +70,7 @@ spec:
           for tag in "${tags_array[@]}"
           do
               echo "Applying tag $tag"
-              skopeo copy docker://$IMAGE docker://$IMAGE_WITHOUT_TAG:$tag
+              skopeo copy --multi-arch all docker://"$IMAGE" docker://"$IMAGE_WITHOUT_TAG:$tag"
           done
         else
           echo "No additional tags specified in the image labels"