Now running `make deb` permanently changes the local git repo :-(. Furthermore if someone did want to change `debian/copyright` their changes wouldn't show up in `git status` if they had previously done a `make deb`

I think the right fix here is to have a copyright header file in each repo, have build-infra cat this this the GPL license terms to form `debian/copyright` and add this to `debian/.gitignore` in each repo.