Types have incorrect default export

[jfirebaugh]

The resolved types use export default, but the JavaScript file uses module.exports = .... This will cause TypeScript under the node16 module mode to think an extra .default property access is required, but that will fail at runtime. These types should use export = ... instead of export default.

See https://arethetypeswrong.github.io/?p=jest-fetch-mock%403.0.3