[GCP] How to fix "Permissions error fetching application.. " while deploying a service to an existing project

It's simple to fix this problem by the following steps:

1. use `gcloud config list` to see the setting of the current project.

2. If the `project` field is used with the project name, using "PROJECT-ID" instead by `gcloud config set project {{ PROJECT-ID }}`.

3. run `gcloud app deploy` again, this problem will be resolved.



# Reference

gcloud app deploy ERROR: Permissions error fetching application [apps/]