I actually have an update checker in a few of my more regularly-updated macros. It stores the macros on my personal server, and a hash value on Github—that way, if someone gets to my personal server and hacks a macro, the update will fail unless they also manage to hack my Github and update the hash values. And honestly, I don't see that being anywhere near worth the effort required.
I posted a working sample version a long time ago; I'm still using that basic updater today. While it's not quite as fiddly as yours, it requires a pretty steep technical learning curve, and you have to update a number of items each time you update a macro.
In short, it's far from perfect, but it works reasonably well for my needs.
-rob.