Drupal 9 compatibility

Thanks for the patch. Here is another one with everything else I could found.

We need only #4. it contains #2

1. +++ b/access_unpublished.info.yml
   @@ -2,5 +2,5 @@ name: 'Access Unpublished'
   +core_version_requirement: ^8.7.7 || ^9
   
   +++ b/composer.json
   @@ -2,6 +2,9 @@
   +        "drupal/core": "^8.7.7 || ^9"
   

   How about ^8 || ^9? I don't think there are any changes here that require ^8.7.7

2. +++ b/tests/src/Functional/AccessTest.php
   @@ -17,7 +17,15 @@ class AccessTest extends BrowserTestBase {
   +  /**
   +   * {@inheritdoc}
   +   */
   +  protected $defaultTheme = 'classy';
   
   +++ b/tests/src/Functional/ContentModerationAccessTest.php
   @@ -19,7 +19,19 @@ class ContentModerationAccessTest extends BrowserTestBase {
   +  /**
   +   * {@inheritdoc}
   +   */
   +  protected $defaultTheme = 'classy';
   
   +++ b/tests/src/FunctionalJavascript/AccessUnpublishedTest.php
   @@ -19,11 +19,14 @@ class AccessUnpublishedTest extends WebDriverTestBase {
   +  protected $defaultTheme = 'classy';
   

   I might be worth a follow-up to make these tests not depend on classy.

How about ^8 || ^9? I don't think there are any changes here that require ^8.7.7

Only 8.7.11 is still supported by drupal. So I don't mind requiring 8.7.7

Fair enough.

Done