Add `--include-git` to `mix igniter.upgrade --all`

[jimsynz]

Is your feature request related to a problem? Please describe.
A client was surprised by the behaviour of igniter.upgrade not matching that of deps.update for git-based dependencies.

Describe the solution you'd like
Either --all should include git dependencies by default or it should have an additional flag to enable them.

Describe alternatives you've considered

mix igniter.upgrade --all && mix deps.update --all

Additional context
Request via an APS client.

[zachdaniel]

Does mix deps.update --all do git dependencies by default?

[jimsynz]

Yes

[zachdaniel]

Ah, so the difficult thing for us is that we don't know what upgraders to run in those scenarios I think. I will have to look into doing this.

[jimsynz]

Makes sense. Maybe just update and if the package has an upgrader (and most won't) then emit a warning about it.