terraform plan or
tfmigrate plan are run in the target
tfaction sets a pull request label
When a pull request of the target
A is merged and
terraform apply or
tfmigrate apply are run in the target
tfaction updates pull request breanches which have a pull request label
A by GitHub API.
By updating pull request branch, the result of CI including uploaded Terraform Plan file is updated.
Otherwise, an uploaded Terraform Plan file becomes stale and it would fail to run