Following the same contract as in Envoy https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/http/ext_authz/v3/ext_authz.proto#extensions-filters-http-ext-authz-v3-extauthz

Signed-off-by: Pushpalanka Jayawardhana <pushpalankajaya@gmail.com>