[watcher] Transition Yoga to Unmaintained

With the new TC resolution the community replaces Extended Maintenance
with Unmaintained status [1].

So this patch transitions stable/yoga branch to Unmaintained as follows:
- tip of the stable/yoga branch is tagged with yoga-eom tag
- unmaintained/yoga branch will be cut from yoga-eom tag
- stable/yoga branch will be deleted

Some further notes:
- there will no longer be official releases off of yoga branch
- backports can be pushed against unmaintained/yoga branch
- openstack-unmaintained-core and <project>-unmaintained-core groups
  will have the rights to merge patches

For further details please read the resolution [1] & review and +1 this
patch if this is correct as soon as possible.

[1] https://governance.openstack.org/tc/resolutions/20230724-unmaintained-branches.html

Change-Id: I1a0ecd5a041443249f915f602624179de773ca43

deliverables/yoga/python-watcherclient.yaml

@@ -11,6 +11,12 @@ releases:
     projects:
       - repo: openstack/python-watcherclient
         hash: 765701da39030df367f27c9c1b8b95b743fb1279
+  - version: yoga-eom
+    projects:
+      - repo: openstack/python-watcherclient
+        hash: 765701da39030df367f27c9c1b8b95b743fb1279
 branches:
   - name: stable/yoga
     location: 3.4.0
+  - name: unmaintained/yoga
+    location: yoga-eom

deliverables/yoga/watcher-dashboard.yaml

@@ -16,7 +16,14 @@ releases:
       - repo: openstack/watcher-dashboard
         hash: 146e547da934c2464ec5f49326eabed0eecfda96
     diff-start: 6.0.0
+  - version: yoga-eom
+    projects:
+      - repo: openstack/watcher-dashboard
+        hash: ee6dc9102ccbb842cbd23d2d1089fcb4e5373036
 branches:
   - name: stable/yoga
     location: 7.0.0.0rc1
-release-notes: https://docs.openstack.org/releasenotes/watcher-dashboard/yoga.html
+  - name: unmaintained/yoga
+    location: yoga-eom
+release-notes:
+  https://docs.openstack.org/releasenotes/watcher-dashboard/yoga.html

deliverables/yoga/watcher.yaml

@@ -16,7 +16,13 @@ releases:
       - repo: openstack/watcher
         hash: 01d74d0a87abe7d89a6ce14ca18c9fc40ae188ef
     diff-start: 7.0.0
+  - version: yoga-eom
+    projects:
+      - repo: openstack/watcher
+        hash: eafc615725cf87a9320c963b0864f7bba191e9f1
 branches:
   - name: stable/yoga
     location: 8.0.0.0rc1
+  - name: unmaintained/yoga
+    location: yoga-eom
 release-notes: https://docs.openstack.org/releasenotes/watcher/yoga.html