Bump etcd to 3.5.21

Author: seunghun1ee

etc/kayobe/kolla/kolla-build.conf

@@ -14,3 +14,7 @@ build_args = {{ (kolla_build_args | default({})).items() | map('join', ':') | jo
 type = git
 location = https://github.com/stackhpc/requirements
 reference = stackhpc/{{ openstack_release }}
+
+[etcd]
+version = 3.5.21
+sha256 = amd64:adddda4b06718e68671ffabff2f8cee48488ba61ad82900e639d108f2148501c,arm64:95bf6918623a097c0385b96f139d90248614485e781ec9bee4768dbb6c79c53f