Bug#1068247: apt-transport-tor: add security-debug mirror to README

[Jakub Wilk]

Package: apt-transport-tor
Version: 0.5

Please add

 * security-debug.backend.mirrors.debian.org 
tor+http://i3hhdhcoozin2qyb5yhhufszgvhz6m2zfy6n6len2gjmetvbnnxcenyd.onion/

to README.md.

--
Jakub Wilk