When trying to apply changes to a vercel_project_environment_variable resource, I'm getting the following error:

│ Error: Invalid value provided
│ 
│   with module.example.vercel_project_environment_variable.foo,
│   on ./vercel.tf line 84, in resource "vercel_project_environment_variable" "foo":
│   84:   target     = [var.vercel_target]
│ 
│ Set item must be one of production, preview, development, got 

This breaks for me in version 0.12 and 0.13, but the same resource declaration works in version 0.11.5. This issue only occurs when using a variable for the target, literal strings work fine.