参照するConfigMapのmd5値をannotationに追加したい

app-config.yml

apiVersion: v1
kind: ConfigMap
metadata:
 name: app-config
data:
 SPECIAL_LEVEL: very
 SPECIAL_TYPE: charm

input.yml

apiVersion: apps/v1
kind: Deployment
metadata:
 name: demo
spec:
 replicas: 1
 selector:
   matchLabels:
     app: demo
 template:
   metadata:
     labels:
       app: demo
   spec:
     containers:
     - image: ghcr.io/making/hello-tanzu
       name: hello-tanzu
       envFrom:
       - configMapRef:
           name: app-config

overlay.yml

#@ load("@ytt:overlay", "overlay")
#@ load("@ytt:data", "data")
#@ load("@ytt:md5", "md5")

#@overlay/match by=overlay.subset({"kind":"Deployment","metadata":{"name":"demo"}})
---
spec:
 template:
   metadata:
     #@overlay/match missing_ok=True
     #@overlay/match-child-defaults missing_ok=True
     annotations:
       app-config-md5: #@ md5.sum(data.read("app-config.yml"))