Azure Function proxy with response header

proxies.json

{
  "$schema": "http://json.schemastore.org/proxies",
  "proxies": {
    "PingProxy": {
      "matchCondition": {
        "route": "/api/v1/{*restOfPath}"
      },
      "backendUri": "https://localhost/api/{restOfPath}",
      "responseOverrides": {
        "response.headers.spl-version": "2018-03-08"
      }
    }
  }
}