[cyborg] 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: I442b497afbb99df23fb2aaf08b3d52cfd3b10ee8

deliverables/yoga/cyborg.yaml

@@ -30,7 +30,13 @@ releases:
     projects:
       - repo: openstack/cyborg
         hash: df5a1bdac86ab5f5d96d599ec452ba360ed9016a
+  - version: yoga-eom
+    projects:
+      - repo: openstack/cyborg
+        hash: df5a1bdac86ab5f5d96d599ec452ba360ed9016a
 branches:
   - name: stable/yoga
     location: 8.0.0.0rc1
+  - name: unmaintained/yoga
+    location: yoga-eom
 release-notes: https://docs.openstack.org/releasenotes/cyborg/yoga.html

deliverables/yoga/python-cyborgclient.yaml

@@ -15,6 +15,12 @@ releases:
     projects:
       - repo: openstack/python-cyborgclient
         hash: 37026cc88903dfeb5c4f9b768b24f8b8db614123
+  - version: yoga-eom
+    projects:
+      - repo: openstack/python-cyborgclient
+        hash: 858aa4a34f88ffbb78d86f22baa630ffef0edcda
 branches:
   - name: stable/yoga
     location: 1.7.0
+  - name: unmaintained/yoga
+    location: yoga-eom