Add --update-refs switch to rebasing commands

[bezbac]

This should resolve #354.

One item from the issue was not implemented:

Possibly default to enabled if rebase.updateRefs is set in git config

I don't believe this is necessary, and I did a quick check to confirm. Enabling the rebase.updateRefs setting globally using git config --global rebase.updateRefs true is already respected by edamagit, since it executes regular git rebase commands that respect this setting.

[bernarduh]

🚀

[spookylukey]

Thanks!