[heat] 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: I17af169f2b042c16bc1a70d09383da348a251554

deliverables/yoga/heat-agents.yaml

@@ -20,7 +20,13 @@ releases:
     projects:
       - repo: openstack/heat-agents
         hash: d8c47efe1f00b0a99e8458564df839cba929b721
+  - version: yoga-eom
+    projects:
+      - repo: openstack/heat-agents
+        hash: d8c47efe1f00b0a99e8458564df839cba929b721
 branches:
   - name: stable/yoga
     location: 4.0.0.0rc1
+  - name: unmaintained/yoga
+    location: yoga-eom
 release-notes: https://docs.openstack.org/releasenotes/heat-agents/yoga.html

deliverables/yoga/heat-dashboard.yaml

@@ -19,7 +19,13 @@ releases:
     projects:
       - repo: openstack/heat-dashboard
         hash: 36ae65ee9da09aa486541740b58ffd6aea748513
+  - version: yoga-eom
+    projects:
+      - repo: openstack/heat-dashboard
+        hash: 36ae65ee9da09aa486541740b58ffd6aea748513
 branches:
   - name: stable/yoga
     location: 7.0.0.0rc1
+  - name: unmaintained/yoga
+    location: yoga-eom
 release-notes: https://docs.openstack.org/releasenotes/heat-dashboard/yoga.html

deliverables/yoga/heat.yaml

@@ -21,7 +21,13 @@ releases:
     projects:
       - repo: openstack/heat
         hash: 41a6b91362c3cf90bd3692c88b9840d6b1a8d56b
+  - version: yoga-eom
+    projects:
+      - repo: openstack/heat
+        hash: 637d3d50695d7ebc06019d43d0a1f8ca1f3ad275
 branches:
   - name: stable/yoga
     location: 18.0.0.0rc1
+  - name: unmaintained/yoga
+    location: yoga-eom
 release-notes: https://docs.openstack.org/releasenotes/heat/yoga.html

deliverables/yoga/python-heatclient.yaml

@@ -15,7 +15,14 @@ releases:
     projects:
       - repo: openstack/python-heatclient
         hash: a9abc54844fd7deb25e6860f1114dd22db367281
+  - version: yoga-eom
+    projects:
+      - repo: openstack/python-heatclient
+        hash: 908771b55d9f17b5a1d8d37c7d34c20642437531
 branches:
   - name: stable/yoga
     location: 2.5.1
-release-notes: https://docs.openstack.org/releasenotes/python-heatclient/yoga.html
+  - name: unmaintained/yoga
+    location: yoga-eom
+release-notes:
+  https://docs.openstack.org/releasenotes/python-heatclient/yoga.html