Add py38 package metadata
Add py38 package metadata

Now that we are running the Victoria tests that include a
voting py38, we can now add the Python 3.8 metadata to the
package information to reflect that support.

Change-Id: I5fcc63ab2ad9a6c5f9cd1a922ef7ea5627c7a396
Signed-off-by: Sean McGinnis <961eeb09b6d45516665e15b82e013282c4faf575@gmail.com>

openstack/watcher-dashboard,openstack/watcher-dashboard,openstack/watcher-dashboard,openstack/watcher-dashboard