Move includes variable

[j7-dev]

Move includes variable to .release-it.cjs or create a separate configuration file and have create-release.cjs require it.

const includes = [
  'inc',
  'js/dist',
  'required_plugins',
  'composer.json',
  'composer.lock',
  'index.php',
  'plugin.php',
  'README.md',
]

This way, users only need to configure it in one place without having to switch files constantly.