[Proposal] Increased probability of falling artefact of Harrower

mis

@Kyronix

Of all the Harrowers I have done, I have yet to see a single artefact.

I think the drop % is too low, I propose to review and increase the drop % because of the time (both for killing the enemy and collecting the skulls) and difficulty (both of the enemy and the possibility of others coming to harm you) involved in doing so.

Thanks