message: jest-transform: Fix optional type for getCacheKey in transform
diff: @@ -56,7 +56,7 @@ export interface Transformer {
  canInstrument?: boolean;
  createTransformer?: (options?: any) => Transformer;
  - getCacheKey: (
  + getCacheKey?: (
  fileData: string,
  filePath: Config.Path,
  configStr: string,
  