Upgrade node-fetch to v3 when we migrate to dual-format (ESM & CJS)

We'll want to upgrade node-fetch to v3 when we publish this module in dual-format. However, we'll want to think carefully about how to import the module in CJS, since we'll still have to support it as well.
 context: https://github.com/googleapis/google-cloud-node/issues/7719