Update to the newest version.

Python 3 is now the default one, so we can drop the suffix from pip
invocation and we have to install it explicitly.

Cc: Petri Latvala <petri.latvala@intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Reviewed-by: Petri Latvala <petri.latvala@intel.com>