Should this not switch to the default branch before running?

[abea]

tag-old-releases/app.js

Line 85 in 76ca427

exec('git checkout --quiet master');

Right now this only switches to the default branch once it's ready to do the tagging. But if you run this while on a feature branch that's a version ahead of the default you will end up with a tag for that "future" version even though it's not actually ready.