Updates for July 18

[bfhealy]

Pull requests

• Fix cronjob issues specific to running in cron environment #439
• Save training stats in json file #440
• Update default GCN cronjob daysAgo #441
• Add test workflow without Kowalski connection #442

Issues

• Need to explicitly specify location of python installation for cron job #435
• Remove call to python in inference scripts #436

Going forward

We will work on:

• Adding documentation to inform transient scanners about SCoPe classifications
• Ingesting DNN/XGB classifications into a new Kowalski collection
• Filling out more parts of the SCoPe paper