Going around a CS research department and asking the population there to justify their cron jobs and other stuff they run sounds like an excellent use of a (rare-ish) university admin / IT staff's time... /s
And deal with the ire of Professor Foo (and grad students Bar and Baz) who want/need to use obscure software XYZ and have done so for years (or decades) without any fuss. And build some interface between your HPC clusters and Github. And keeping with regulations and agreements on privacy and security. And so on and so forth. All that for the low, low cost of... Well, certainly not less than keeping and maintaining like one to three unix machines that don't need no fancy hardware or other special attention in the data center you are maintaining anyway?! Why?
edit: By the way, from their documentation, the department mentioned by the author runs their own E-Mail-Servers (as many universities do - fortunately, in this world, there often still is a bit more choice than 'use Gmail/Outlook in the browser').