fix for failing az containerapp create command

in az containerapp create the image needs double quotes, otherwise the exception 
`The following field(s) are either invalid or missing. Invalid value: "/albumapp-ui": GET https:: UNAUTHORIZED: authentication required; [map[Action:pull Class: Name:albumapp-ui Type:repository]]: template.containers.album-ui.image.` is thrown.

Propose change: image "$ACR_NAME.azurecr.io/albumapp-ui"

Author: owingruters

articles/container-apps/communicate-between-microservices.md

@@ -241,7 +241,7 @@ az containerapp create `
   --name $FRONTEND_NAME `
   --resource-group $RESOURCE_GROUP `
   --environment $ENVIRONMENT `
-  --image $ACR_NAME.azurecr.io/albumapp-ui  `
+  --image "$ACR_NAME.azurecr.io/albumapp-ui"  `
   --env-vars API_BASE_URL=https://$API_BASE_URL `
   --target-port 3000 `
   --ingress 'external' `
@@ -283,4 +283,4 @@ az group delete --name $RESOURCE_GROUP
 ## Next steps
 
 > [!div class="nextstepaction"]
-> [Environments in Azure Container Apps](environment.md)
+> [Environments in Azure Container Apps](environment.md)