drupal 8 custom page template (suggestion) based on content types (page--[content-type].html.twig)

page-template-content-type.php

<?php
/**
 * Implements hook_theme_suggestions_HOOK_alter().
 *
 * This hook for adding a custom suggestion page template.
 *
 * Place this function in your THEME_NAME.theme file.
 * then you can use the template page--[content-type].html.twig
 *
 * Tested and worked with Drupal Version 8.3.x
 */
function THEME_NAME_theme_suggestions_page_alter(array &$suggestions, array $variables) {
  if ($node = \Drupal::routeMatch()->getParameter('node')) {
    $content_type = $node->bundle();
    $suggestions[] = 'page__'.$content_type;
  }
}