@ramsey Just: Don't.
The subject lines space is limited and should not be wasted for stuff that doesn't belong there.
Also the prime idea behind conventional commits is to add machine readable info.to the commit message: Fine. Do so. The commit.meysage can be as long as you want. Add it there. Keep the subject line to the human readable part.
Also: Creating changelogs from.git.commits is *not* what chamgelogs are there for.
Keep a changelog can help on *that* front.