Update README.md

[e-wai]

Make sure everyone knows to adjust the pytest command because API key isn't publicly available

[ufshk]

OK but there's one problem.

The tests never needed the API key originally :D

That is a good thing right?

(I just mocked responses.)

[e-wai]

Uhh am I just reading these wrong ->

strategy/routemodel/tests/test_data_retrieval.py

Lines 79 to 91 in ebf5b40

	def test_elevation_getter_good_inputs():
	waypoints = [{"45": "-74"}, {"46": "-75"}]
	viawaypoints = [[{"45.5": "-74.5"}]]
	elev = ElevationDataRetrieval(waypoints, viawaypoints)
	response = elev.get_elevation_data()
	assert(response.status_code == 200)
	def test_elevation_getter_bad_inputs():
	waypoints = [{}, {}]
	viawaypoints = [[{}]]
	elev = ElevationDataRetrieval(waypoints, viawaypoints)
	response = elev.get_elevation_data()
	assert(response.status_code == 500)

[ufshk]

ok so not all of them used mock responses, but I intend that they do now, since we can't use the key