Introduce newton support in releases_and_versioning.rst
Introduce newton support in releases_and_versioning.rst

Issues:
Fixes #201

Problem:
We need to update the releases_and_versioning.rst file to indicate
newton support for LBaaSv2

Analysis:
Updated the doc with current support for newton

Tests:

F5Networks/f5-openstack-docs,jputrino/f5-openstack-docs