merge-core.pl: Strip out import-into.t test

Signed-off-by: Niels Thykier <niels@thykier.net>
autodie.pm: Mention the GitHub issue tracker for bugs

We tend to be better af reacting to issues in the GitHub issue
tracker, so it makes sense to mention it next to (and also before) the
CPAN Request Tracker.

Signed-off-by: Niels Thykier <niels@thykier.net>