Creating / updating project environment variables using `createProjectEnv` in custom environment

[reck753]

Hi all, I am trying to upsert an environment variable in a project but I am having difficulties to find a way how to do it for a specific custom environment.

createProjectEnv supports target field in requestBody but it is limited only to built-in environments production, preview and development and it will fail with Zod validation error if anything else is provided, e.g. staging in my case.