Add ability to configure VLAN tag on patch port

Change-Id: I41f6e9c4feed93d03ac0479f9bd3626e48ad8063
Co-Authored-By: Michael Polenchuk <mpolenchuk@mirantis.com>
Closes-Bug: PROD-20729
diff --git a/README.rst b/README.rst
index 45139c4..45c045d 100644
--- a/README.rst
+++ b/README.rst
@@ -1146,6 +1146,7 @@
             bridge: br-ens7
             port_type: patch
             peer: prv-ens7
+            tag: 109 # [] to unset a tag
             mtu: 65000
           patch-br-prv-br-ens7:
             enabled: true
@@ -1155,6 +1156,7 @@
             type: ovs_port
             port_type: patch
             peer: ens7-prv
+            tag: 109
             mtu: 65000
           ens7:
             enabled: true