Switch to the "new" jcrop

The old one didn't work with recent versions of node. The patched one
does. This also replaces the github dep with a real npm registry one.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>
Signed-off-by: nextcloud-command <nextcloud-command@users.noreply.github.com>