Broken link to NASA web map service

This cookbook is failing the link checker test with a dead link to https://www.earthdata.nasa.gov/technology/web-map-service-wms

@ahuang11 do you have a suggestion for an updated link for the [References section of the Introduction notebook](https://projectpythia.org/web-map-feature-services-cookbook/notebooks/introduction.html#resources-and-references)?