fix(export): Forgot exporting MiddlewareUtils

Author: nutgaard

src/yet-another-fetch-mock.ts

@@ -117,4 +117,5 @@ export default FetchMock;
 
 export { default as MatcherUtils } from './matcher-utils';
 export { default as ResponseUtils } from './response-utils';
+export { default as MiddlewareUtils } from './middleware-utils';
 export * from './types';