[watcher] 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: Iab0dee53ddf112cdf0dbbe29b155764199d2d88d

deliverables/zed/python-watcherclient.yaml

@@ -11,6 +11,12 @@ releases:
     projects:
       - repo: openstack/python-watcherclient
         hash: e227f82fd63bc5d47492da3e3c2ed70182093ed9
+  - version: zed-eom
+    projects:
+      - repo: openstack/python-watcherclient
+        hash: e7b9945933ba7062d9a18afda3de174904ccdecf
 branches:
   - name: stable/zed
     location: 4.0.0
+  - name: unmaintained/zed
+    location: zed-eom

deliverables/zed/watcher-dashboard.yaml

@@ -16,7 +16,13 @@ releases:
       - repo: openstack/watcher-dashboard
         hash: b526383ebae37f3bdb6ef4be9245684967c46d65
     diff-start: 7.0.0
+  - version: zed-eom
+    projects:
+      - repo: openstack/watcher-dashboard
+        hash: 1c0c1bd902bc285d639b5555383c04cfc785c3f7
 branches:
   - name: stable/zed
     location: 8.0.0.0rc1
+  - name: unmaintained/zed
+    location: zed-eom
 release-notes: https://docs.openstack.org/releasenotes/watcher-dashboard/zed.html

deliverables/zed/watcher.yaml

@@ -20,7 +20,13 @@ releases:
       - repo: openstack/watcher
         hash: 2b103c40a7eee5f2395db8779c380a95f7f7ca47
     diff-start: 8.0.0
+  - version: zed-eom
+    projects:
+      - repo: openstack/watcher
+        hash: 003b19317bde4cb212f78def0da3113b543138d3
 branches:
   - name: stable/zed
     location: 9.0.0.0rc1
+  - name: unmaintained/zed
+    location: zed-eom
 release-notes: https://docs.openstack.org/releasenotes/watcher/zed.html