v7.0.6

• Changed WorkerMessenger constructor option worker from Worker | DedicatedWorkerGlobalScope to a structural WorkerLike
  (Pick<Worker, 'postMessage' | 'addEventListener' | 'removeEventListener'>). This prevents generated Penpal declaration files from requiring DedicatedWorkerGlobalScope, fixing TS2304 for consumers that do not include the webworker lib (see #108).