#### Rebase all commits from the `root` commit and sign them with the (new) gpg key

```bash
git rebase --root --gpg-sign --committer-date-is-author-date --root  
```

#### Rebase all commits from the `root` commit, sign them with the new key and reset the author

```bash
git rebase --exec 'git commit --amend --no-edit -n -S --reset-author --quiet' --committer-date-is-author-date --root
```