Update default ICESat-2 Version to 7

[scottyhq]

we search by STAC collection which includes the version in the collection name:

coincident/src/coincident/datasets/nasa.py

Line 29 in 0df07e6

default_factory=lambda: ["ATL03_006"]

The main thing to be aware of is the CRS from ITRF2014 to ITRF2020

see also: https://uw-cryo.github.io/3D_CRS_Transformation_Resources/readme#itrf-epsg

xref: SlideRuleEarth/sliderule#534