correct custom url for previews

Author: hry-gh

.github/workflows/preview.yml

@@ -54,3 +54,4 @@ jobs:
           source-dir: ./public/
           umbrella-dir: ./pr-preview/
           deploy-repository: ${{ env.DEPLOY_REPO_OWNER }}/${{ env.DEPLOY_REPO }}
+          custom-url: "https://ref.opendre.am/"