ci: cache pytype-related files between runs

9 jobs for topic/default/pytype-cache in 20 minutes and 9 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Test
passed #55017
doc

00:00:28

passed #55011
flake8

00:00:22

passed #55687
manual
pytype

00:15:53

passed #55013
tests-py2-cext

00:04:14

passed #55014
tests-py2-pure

00:04:15

passed #55015
tests-py3-cext

00:03:23

passed #55016
tests-py3-pure

00:02:33

passed #55018
manual
pytype

00:16:11

passed #55012
manual
pytype

00:15:44