Elasticbeanstalk modifying php-fpm with .ebextensions

I am trying to make modifications on php-fpm configs. I have searched and tried a lot but I am not able to do it.

Here is my config files;

This one is not effected anything

files:
  "/etc/php-fpm.d/www.conf" :
    mode: "000644"
    owner: root
    group: root
    encoding: plain
    content: |
      pm.max_children = 500

And this one gives me an error.

files:
  "/etc/php-fpm.d/00_php-fpm.conf" :
    mode: "000644"
    owner: root
    group: root
    encoding: plain
    content: |
      pm.max_children = 500
      pm.start_servers = 5

Thank you for your answers.