Update build-and-publish.yml

added default input app that maps to APP_NAME

.github/workflows/build-and-publish.yml

@@ -11,6 +11,7 @@ on:
         description: "name of application folder under infra directory"
         required: true
         type: string
+        default: "app"
       ref:
         description: The branch, tag or SHA to checkout. When checking out the repository that triggered a workflow, this defaults to the reference or SHA for that event. Otherwise, use branch or tag that triggered the workflow run.
         required: true