Additional Media Types (KML)

[Alex I. Mandel]

There are some fairly common and standard(OGC) MediaTypes not current listed in https://github.com/stac-utils/pystac/blob/main/pystac/media_type.py
In particular KML and KMZ which seem to be common sidecar files on a lot of Collections.

I can make a PR for

KML = "application/vnd.google-earth.kml+xml"

Opened this ticket to track, and solicit if we're missing some other obvious candidates?

[Pete Gadomski]

Closed by #1151