Add new Ubuntu packager to ReleasingTor.md
An Ubuntu packager has been found and is super willing to continue his great work already.
Here is some of the ongoing work to get Xenial (16.04 LTS) to migrate to 029.
https://bugs.launchpad.net/ubuntu/+source/tor/+bug/1710753
That being said, we should add him to the ReleasingTor.md
so he gets notified when a new tarball is released.