Enable STAC Output

[scottyhq]

CMR supports STAC result format for collection/granule retrieval and granule searches: https://cmr.earthdata.nasa.gov/search/site/docs/search/api.html#stac

But currently python_cmr doesn't support it:

python_cmr/cmr/queries.py

Lines 48 to 51 in fb58457

	_valid_formats_regex = [
	"json", "xml", "echo10", "iso", "iso19115",
	"csv", "atom", "kml", "native"
	]

It would be great to support this output format! I made some small changes on a new branch to allow this develop...scottyhq:python_cmr:stac let me know if you're open to a pull request.

Basic usage:

api = GranuleQuery() 
search = api.parameters(
    point=(-105.78, 35.79),
    temporal=('2021-02-01','2021-03-01'),
    collection_concept_id='C2021957657-LPCLOUD'  # Required for STAC search
)
items = search.format("stac").get()

[chuckwondo]

Sure thing! Please do submit a PR.

[chuckwondo]

Fixed by #82