Removing python3.6 and replacing it with more recent versions. Pick-to: 6.4 6.5 Change-Id: If8cd4c369e4fc9ff8dc7d53865b80b588f278091 Reviewed-by: Tony Sarajärvi <tony.sarajarvi@qt.io> Reviewed-by: Jukka Jokiniva <jukka.jokiniva@qt.io>