Support upgrades after adopting the template

[hamlim]

Context:

Right now - we're iterating on this template quite a bit, and there's a number of projects that used it as a starting point.

Which means that there's a number of projects that are using slightly older versions of the template, and they don't have an easy way to adopt the changes without manually reviewing the changes made here (based on releases/tags/commits etc).

Ideally - we'd have a "simple" CLI that would let repos upgrade their features (in a non-destructive way) that would allow them to adopt the newer changes as they are released.

[hamlim]

I could see us adding a config file at the root of the repo that manages the version of the template used, and that way the CLI knows the diff between the two (somehow).

It might mean that we'll need to write a bit of code that handles the upgrades for us however...