Automatically delete pages in workshops/_posts/ that don't have corresponding repos #16
Description
A repo for a Feb 2020 workshop was created, but the date was pushed back to May. The original Feb repo was deleted, but the page for it in the website repo (workshops/_posts/) still existed. I deleted it manually (commit 985ba757, but in the future it'd be cool if those were deleted automatically by the update-workshops.py script.