title: Can't download php modules inside the docker container
body: <p>I can't download any php extensions inside my docker container, when trying 
  <code>yum install php7.3-mysql</code> it gives me error </p>
  
  <blockquote>
    <p>"No package php7.3-zip available."</p>
  </blockquote>
  
  <p>And when trying with <code>docker-php-ext-install</code> it gives me </p>
  
  <blockquote>
    <p>"bash: docker-php-ext-install: command not found"</p>
  </blockquote>
  
  <p>The docker container was created from the centos official image, just pulled it and installed php7.3 successfully but not the extensions</p>