Maxchars is set to only 200 chars

I tested the patch in the following way:

• Installed page_specific_class via composer
• Enabled the module/li>
• Confirmed that I was only able to enter 200 characters at/admin/config/page-class/settings
• Added this patch to composer:
  

  "patches": {
        "drupal/page_specific_class": {
          "Maxchars is set to only 200 chars": "https://www.drupal.org/files/issues/2020-02-21/3115032-4.patch"
        }
      }

• Installed the patch with composer install
• Navigated back to /admin/config/page-class/settings
• Entered a number of class strings longer than 200 characters and saved
• Visited a page set for a custom class to confirm the body class was there

@dimitri.baudonck@dukeandgrace.com , @Danny Englander thanks for patch and for review. I have pushed this issue in 8.x-1.x branch.

#4 worked for me. Thanks a lot.