Added python3 packages for mellanox agent container
Added python3 packages for mellanox agent container

https://review.opendev.org/#/c/672023 added mellanox agent
container which contains python2 packages but on RHEL8 tripleo
job, python3 packages are needed which broke the periodic
container build job, including python3 packages will
fix the issue.

Closes-Bug: #1855050

Change-Id: I35909eccaa101ef498d0a3481b8708d8ee5884d3
Signed-off-by: Chandan Kumar (raukadah) <37614c4f126be5146599b9d19fe2ba37ae0ea495@redhat.com>

openstack/kolla,stackforge/kolla,rahulunair/kolla,stackforge/kolla,rahulunair/kolla,stackforge/kolla,openstack/kolla