Reading from a secret in Traefik Middleware

Question

I am working on a middleware using traefik that basically adds a Authorization header and wondering how I can read that header from a secret that already exists. Below is the middleware script

apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: middleware-tokenheader
spec:
  headers:
    customRequestHeaders:
      Authorization:  {{ .Values.token  }}