Generated flow types breaking flow checking in downstream repo

[sandersky]

Now that this project is generating Flow type files at lib/*.flow, they are breaking Flow type checking in downstream repos with the following error:

Error: node_modules/nodely/lib/master.js.flow:21
 21: declare export default function(argv: $Exact<{output: string, source: string, target: string, verbose: boolean, watch: boolean, workerCount: number}>): {erred: boolean, isWatching: boolean, queue: Array<$Exact<{filePath: string, type: any | any}>>, workers: Array<$Exact<{idle: boolean, worker: Class0}>>};
                                    ^ Unexpected token (

Error: node_modules/nodely/lib/worker.js.flow:9
  9: declare export default function(argv: $Exact<{output: string, source: string, target: string, verbose: boolean, watch: boolean, workerCount: number}>): void;
                                    ^ Unexpected token (

See: facebook/flow#2830

[sandersky]

I've manually fixed these for now by hand by replacing declare export default function(…): … with declare export default (…) => ….