Mark Python 3.9 supported
Mark Python 3.9 supported

... because CentOS Stream 9 has Python 3.9.

Change-Id: I87929a7b94426f9a5d176131dc9a850d15c9084b

fr34k8/packstack,fr34k8/packstack,mahak/packstack,mahak/packstack,fr34k8/packstack,mahak/packstack