Whether Paul VI was beatified, canonized, or not (which is an entirely separate discussion, but TL;DR: canonizations are secondary objects of the Church’s infallibility with regards to her universal ecclesiastical laws; a true Pope is protected by the Holy Ghost from declaring someone as a saint [and therefore eligible for the veneration of the laity, and the general worship in the liturgy] who in fact isn’t
; thus, if Francis is the Pope, then his beatification and canonization of Paul VI is legitimate), that has nothing to do with the papal authority to revise the liturgy.