[VOL-5009] - Create a v2.12 release notes page.

overview/releases.rst
release_notes/index.rst
release_notes/voltha_2.12.rst
-----------------------------
  o Create a skeleton release notes area for v2.12

Change-Id: Ia74075131326e0254af236d9c9edbdf8f46fa430
diff --git a/makefiles/virtualenv.mk b/makefiles/virtualenv.mk
index bcda734..fd178f3 100644
--- a/makefiles/virtualenv.mk
+++ b/makefiles/virtualenv.mk
@@ -14,6 +14,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 ## -----------------------------------------------------------------------
+# https://gerrit.opencord.org/plugins/gitiles/onf-make
+# ONF.makefile.version = 1.0
+# -----------------------------------------------------------------------
 
 $(if $(DEBUG),$(warning ENTER))