[nova] Transition Zed to Unmaintained

This branch reached the end of its official stable maintained period,
hence this patch transition stable/zed branch to Unmaintained. (For
details about Unmaintained state please see: [1][2])

The transitions is as follows:
- tip of the stable/zed branch is tagged with zed-eom tag
- unmaintained/zed branch will be cut from zed-eom tag
- stable/zed branch will be deleted

Note:
- there will no longer be official releases off of zed branch after this
  transition
- backports can be pushed to unmaintained/yoga branch
- openstack-unmaintained-core (or <project>-unmaintained-core groups if
  such exists) have the rights to merge patches

Important: please +1 if the team is ready for us to proceed with this
transition, or -1 if there are any final Zed stable release with
backports currently in flight that we should wait for. For the latter
case, please propose a final Zed stable release patch, and rebase this
patch on top of that, with the latest commit hash of stable/zed.

The transition deadline is May 2nd, 2024. [3]

[1] https://docs.openstack.org/project-team-guide/stable-branches.html#unmaintained
[2] https://governance.openstack.org/tc/resolutions/20230724-unmaintained-branches.html
[3] https://releases.openstack.org

Change-Id: I967bce9be73e0320b2ec1b4b840c969a549c41c7

deliverables/zed/nova.yaml

@@ -65,7 +65,13 @@ releases:
     projects:
       - repo: openstack/nova
         hash: 3d1a705fc85a0f0a46e7cbc322e98fff892e21b8
+  - version: zed-eom
+    projects:
+      - repo: openstack/nova
+        hash: 3d1a705fc85a0f0a46e7cbc322e98fff892e21b8
 branches:
   - name: stable/zed
     location: 26.0.0.0rc1
+  - name: unmaintained/zed
+    location: zed-eom
 release-notes: https://docs.openstack.org/releasenotes/nova/zed.html

deliverables/zed/os-vif.yaml

@@ -20,7 +20,13 @@ releases:
     projects:
       - repo: openstack/os-vif
         hash: 51b7f486318d1b2d61f2079b615cc406dca10188
+  - version: zed-eom
+    projects:
+      - repo: openstack/os-vif
+        hash: 51b7f486318d1b2d61f2079b615cc406dca10188
 branches:
   - name: stable/zed
     location: 3.0.0
+  - name: unmaintained/zed
+    location: zed-eom
 release-notes: https://docs.openstack.org/releasenotes/os-vif/zed.html

deliverables/zed/osc-placement.yaml

@@ -11,7 +11,13 @@ releases:
     projects:
       - repo: openstack/osc-placement
         hash: aa14e9ccde590b95573c5aa10d386480c1c0eb3b
+  - version: zed-eom
+    projects:
+      - repo: openstack/osc-placement
+        hash: d4036554f044f548d6ba460db0114c0fd7469f7b
 branches:
   - name: stable/zed
     location: 4.0.0
+  - name: unmaintained/zed
+    location: zed-eom
 release-notes: https://docs.openstack.org/releasenotes/osc-placement/zed.html

deliverables/zed/placement.yaml

@@ -17,7 +17,13 @@ releases:
       - repo: openstack/placement
         hash: 5ec38f6d3b76619fac442a85a9b5c73dc606b83a
     diff-start: 7.0.0
+  - version: zed-eom
+    projects:
+      - repo: openstack/placement
+        hash: d7ced6bd2fc82caf458f20b5652888164b1bbb70
 branches:
   - name: stable/zed
     location: 8.0.0.0rc1
+  - name: unmaintained/zed
+    location: zed-eom
 release-notes: https://docs.openstack.org/releasenotes/placement/zed.html

deliverables/zed/python-novaclient.yaml

@@ -15,7 +15,13 @@ releases:
     projects:
       - repo: openstack/python-novaclient
         hash: be9517cb027d960caf4c9c8171b3ad2568bedae9
+  - version: zed-eom
+    projects:
+      - repo: openstack/python-novaclient
+        hash: 7c3f3bc615cb91cd0106f91b0452bf7968ff3598
 branches:
   - name: stable/zed
     location: 18.1.0
+  - name: unmaintained/zed
+    location: zed-eom
 release-notes: https://docs.openstack.org/releasenotes/python-novaclient/zed.html