How to hide nginx version in elastic beanstalk

I am running an app on the platform Ruby 2.2 (Passenger Standalone) and wish to hide the nginx version from the HTTP headers. I am not using Docker. Other Stack Overflow answers have recommended adding this to my .ebextensions:

00_nginx.conf:

files:
  "/etc/nginx/conf.d/proxy.conf" :
    mode: "000644"
    content: |
      server_tokens off;

However this does nothing. Should I be putting the file in a different spot?