Hi Jean,
Thanks for your post,
From the error message I would think that your IAM permission was somehow modified from last week. Apparently your user doesn’t have the “serviceusage.apiKeys.update” permission. This permission is granted in different roles that you can find here :
Owner (roles/owner)
Editor (roles/editor)
API Keys Admin (roles/serviceusage.apiKeysAdmin)
Also here is a quickstart for IAM if you are not familiar with granting permission to a user.