Code review comment for ~athos-ribeiro/git-ubuntu:leaking-perl

Summary of realtime chat with Athos:

1) Split out sed changelog parsing changes to separate MP; 2) Adjust main fix to use pattern of wrappers in $SNAP/usr/local/bin instead of a shebang that requires on host /usr/bin/env using existing pattern; 3) Test endpoints directly in separate test as much as possible using existing pattern.