Neutron stable releases (Train, Ussuri, Victoria)

To go along with Wallaby-2 milestone

Victoria/Ussuri version bumps are for RPC version upgrade [1] backports

[1] https://review.opendev.org/c/openstack/neutron/+/764108

Change-Id: I10f4e1e24486d59217a6a21d11f003c1ace73c37

deliverables/train/neutron.yaml

@@ -43,6 +43,10 @@ releases:
     projects:
       - repo: openstack/neutron
         hash: fa5967012d201a7bc3a407280fd7481f5dc81574
+  - version: 15.3.1
+    projects:
+      - repo: openstack/neutron
+        hash: c631119117f1c21341e57739d4a4aeeff8764fd7
 cycle-highlights:
   - When different subnet pools participate in the same address scope,
     the constraints disallowing subnets to be allocated from different

deliverables/ussuri/neutron.yaml

@@ -31,6 +31,10 @@ releases:
     projects:
       - repo: openstack/neutron
         hash: 70d0a7e769a88330118dde7073bdcb4bab04ba7c
+  - version: 16.3.0
+    projects:
+      - repo: openstack/neutron
+        hash: 3ff0a604677503bd6066e99681c17d7f29027831
 cycle-highlights:
   - The ``OVN`` driver is now merged into Neutron repository and is
     one of the in-tree Neutron ML2 drivers, like ``linuxbridge`` or

deliverables/victoria/neutron.yaml

@@ -30,6 +30,10 @@ releases:
       - repo: openstack/neutron
         hash: f7282d909ed3f5834748995b00b70413f1b43495
     diff-start: 16.0.0.0rc1
+  - version: 17.1.0
+    projects:
+      - repo: openstack/neutron
+        hash: 0a02297ea944896328bbb5722d05d8225609f36f
 branches:
   - name: stable/victoria
     location: 17.0.0.0rc1