The method linkify just added links for an entry to a list and produced
duplicates if we got more than one changelog line in a PR. We now only
produce a link once per PR.
Signed-off-by: Peter Neuroth <pet.v.ne@gmail.com>
The links were rather annoying in the flowing text, so extract them
and add them to the footer of the release instead. This uses the
shorthand and footnote style of links.
Since the `CHANGELOG.md` file is a major source for merge conflicts I decided
to build a tiny tool that generates the entries for the changelog
automatically from the commit messages.