pglogical 2's maintenance happens on the REL2_x_STABLE branch, check that out instead.
pglogical3 is currently only available for 2ndQuadrant support customers. Follow the 2ndQuadrant blog and [email protected] or the bdr/pglogical forum and mailing list at https://groups.google.com/a/2ndquadrant.com/forum/#!forum/bdr-list for updates.