v4.2.0

Added

• Several workspaces in one configuration file: a workspaces list with shared defaults, one webhook receiver for
  all of them that routes each delivery by repository and ref, a state file per workspace and --workspace (-w)
  for update, status, rollback and start.
• Blue-green deployments (workspace.strategy: "blue-green"): the next version is prepared in a second checkout
  while the old one runs, a symlink (a junction on Windows) switches between them, and a rollback only moves the link
  back.
• Status endpoint next to the webhook receiver (webhook.statusPath, webhook.statusToken) that reports what each
  workspace runs, for monitoring systems.
• The configuration builder offers the strategy and the status endpoint.