Code review comment for ~sespiros/ubuntu-security-tools/+git/ubuntu-security-tools:fix-release-info

I am not in love with changing so much code to use a new name... although I can understand the motivation. What about a different word than base_release - since this is what we would use in the changelog entry, looking at it for inspiration https://www.debian.org/doc/debian-policy/ch-source.html#s-dpkgchangelog I see they use the term distribution(s) - what if we used that instead?