needs to be https:// to work with opsec network restrictions in scl3
The problem with http/https is that git will pull down each object one at a time with separate http requests and it's highly fragile. So on SUMO, we've been using git (and switching the older urls to git, too) because otherwise when doing a git submodules update, it's more likely to fail using http/https. Plus with large repositories, the chance of failing goes even higher.
Do you really want to switch to http/https? It means that you're chances of getting a failure when updating are much higher and it'll probably mean the probability you'll have to sort out bad deployments is much higher.
This is required because the server that does the Git pulls is not able to speak Git:// to the Internet. This is a network security change that has occurred since the last time we pushed staging.