bin/get-amy.py: additionally sort events by slug too
bin/get-amy.py: additionally sort events by slug too

Originally workshops were sorted by start date only, now they're sorted
by slug as well.

k8hertweck/website,swcarpentry/website,swcarpentry/website,gvwilson/website,pbanaszkiewicz/website,k8hertweck/website,pbanaszkiewicz/website,rgaiacs/swc-website,pbanaszkiewicz/website,swcarpentry/website,gvwilson/website,gvwilson/website,ErinBecker/website,rgaiacs/swc-website,ErinBecker/website,gvwilson/website,k8hertweck/website,ErinBecker/website,rgaiacs/swc-website,swcarpentry/website,k8hertweck/website,gvwilson/website,k8hertweck/website,ErinBecker/website,swcarpentry/website,rgaiacs/swc-website,pbanaszkiewicz/website,ErinBecker/website,rgaiacs/swc-website,pbanaszkiewicz/website