title: How to add multiple access_by_lua_file directive under same location = /_sample
body: <p>Using openidc module introspection under location and calling using below,</p>
  
  <pre><code> Policy section
  #
  location = /_sample {
      internal;
      set $api_name "sample"; 
      access_by_lua_file /etc/nginx/path/oauth_introspection.lua;
       Proxypass......
  }
  </code></pre>
  
  <p>Now i want to include below lua file to add some contents and validate something under the same request.</p>
  
  <pre><code> Policy section
  #
  location = /_sample {
      internal;
      set $api_name "sample"; 
      access_by_lua_file /etc/nginx/path/oauth_introspection.lua;
          access_by_lua_file /etc/nginx/path/do_something.lua; //Error with duplicate
       Proxypass......
  }
  </code></pre>
  
  <p>And my oauth_introspection.lua has this openidc introspect logic,</p>
  
  <pre><code>local res, err = require("resty.openidc").introspect(opts)
  </code></pre>