New Upstream version

This relates to https://bugs.debian.org/1008258

Just for personal interest, I thought I'd see how difficult it would be to grab the new version.

Answer: Not very :-)

If nothing else, you might like to cherry-pick philh/twitter-bootstrap4@daa6653a which ensures that uscan only consider 4.* versions, and thus prevents gbp from attempting to upgrade to v5.*.

WARNING: I've made no attempt to test this beyond pointing diffoscope at the result of building it and seeing that a plausible number of changes seemed to exist between the two versions -- I don't know enough javascript to do much more.

HTH

Cheers, Phil.