Release python-openstackclient 6.2.0 and create branch stable/2023.1

CWI deliverables deadline for antelope is over and at this point every
projects should be branched.

Change-Id: I51303eee5a3bd6c6925115a05ad7d19e1509838e

deliverables/antelope/python-openstackclient.yaml

@@ -11,3 +11,10 @@ releases:
     projects:
       - repo: openstack/python-openstackclient
         hash: ec01268ea93141439542fb162a6a12bc2bf533fe
+  - version: 6.2.0
+    projects:
+      - repo: openstack/python-openstackclient
+        hash: 05d34ffce9e710021b0d125add38f2fd73c7852d
+branches:
+  - name: stable/2023.1
+    location: 6.2.0