chore: append arg

Author: scotwells

config/default/manager_metrics_patch.yaml

@@ -1,4 +1,4 @@
 # This patch adds the args to allow exposing the metrics endpoint using HTTPS
 - op: add
-  path: /spec/template/spec/containers/0/args/0
+  path: /spec/template/spec/containers/0/args/-
   value: --metrics-bind-address=:8443