Use tagged release of stackhpc-image-elements

Author: MoteHue

etc/kayobe/stackhpc.yml

@@ -201,5 +201,5 @@ stackhpc_ca_secret_store: openbao
 stackhpc_dib_image_elements_repos:
   - repo: "https://github.com/stackhpc/stackhpc-image-elements"
     local: "{{ source_checkout_path }}/stackhpc-image-elements"
-    version: "fix-heredoc"
+    version: "v1.6.4"
     elements_path: "elements"