There is currently no GPLv4, so this change has no effect at the moment. In case the GPLv4 arrives and I am not alive to approve/review it, the lesser of evils is have give blanket approval of all future GPL versions (as published by the FSF). The worse evil is to be stuck with a license which cannot guarantee the Free-ness of this project in the future. This unfortunately means the FSF can theoretically come out with license terms I do not agree with, but the GPLv2 and GPLv3 will always be an option to all users.
|unicorn_http||license: allow all future versions of the GNU GPL|