BUG: ZTFDATA directory not found

[JannisNe]

Describe the bug
The latest commit explicitly uses os.environ["ZTFDATA"]. If that is not given will cause KeyError.

To Reproduce
Run neutrino_gcn_parser.ipynb until nu.plot_overlap_with_observations(). If you have not specified the env variable ZTFDATA this will raise KeyError

Expected behavior
No Error. This should work with the ztfquery default.

Solution
Use LOCALSOURCE from ztfquery.io instead.

[JannisNe]

fixed by this commit