[BEAM-13657] Update Python version used by mypy. (#22804)
[BEAM-13657] Update Python version used by mypy. (#22804)


lukecwik/incubator-beam,chamikaramj/beam,apache/beam,chamikaramj/beam,apache/beam,apache/beam,chamikaramj/beam,lukecwik/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,apache/beam,apache/beam,lukecwik/incubator-beam,apache/beam,apache/beam,apache/beam,lukecwik/incubator-beam,lukecwik/incubator-beam,apache/beam,chamikaramj/beam,lukecwik/incubator-beam,chamikaramj/beam,lukecwik/incubator-beam,apache/beam,apache/beam,lukecwik/incubator-beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam