chore: update artman version in CI (#2906)
chore: update artman version in CI (#2906)

* chore: update artman version in CI

* try with python3

googleapis/gapic-generator,googleapis/gapic-generator,googleapis/gapic-generator,googleapis/gapic-generator,googleapis/gapic-generator,googleapis/gapic-generator,googleapis/gapic-generator