[solum] 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: Icbad4a20802203cdf8e5015cf8b70bfa313f3078

deliverables/yoga/python-solumclient.yaml

@@ -14,6 +14,12 @@ releases:
     projects:
       - repo: openstack/python-solumclient
         hash: 04722bbed80c9bd75253876031307b5e5abfefa3
+  - version: yoga-eom
+    projects:
+      - repo: openstack/python-solumclient
+        hash: 04722bbed80c9bd75253876031307b5e5abfefa3
 branches:
   - name: stable/yoga
     location: 3.5.0
+  - name: unmaintained/yoga
+    location: yoga-eom

deliverables/yoga/solum-dashboard.yaml

@@ -15,6 +15,12 @@ releases:
       - repo: openstack/solum-dashboard
         hash: a9d4f857b10b564398c06f7c69e9240c960db99b
     diff-start: 7.0.0
+  - version: yoga-eom
+    projects:
+      - repo: openstack/solum-dashboard
+        hash: 0e1623a6228cea2d29f745682b55bc810c1d7945
 branches:
   - name: stable/yoga
     location: 8.0.0.0rc1
+  - name: unmaintained/yoga
+    location: yoga-eom

deliverables/yoga/solum.yaml

@@ -19,7 +19,13 @@ releases:
     projects:
       - repo: openstack/solum
         hash: 54e88e4d2789aabeb7c46b906eb0de946a394e37
+  - version: yoga-eom
+    projects:
+      - repo: openstack/solum
+        hash: 391e38a757151a8074037a9f8ae4c54af6af02d7
 branches:
   - name: stable/yoga
     location: 12.0.0.0rc1
+  - name: unmaintained/yoga
+    location: yoga-eom
 release-notes: https://docs.openstack.org/releasenotes/solum/yoga.html