Bump phpunit/phpunit from 7.5.20 to 9.5.3

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 7.5.20 to 9.5.3.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/master/ChangeLog-9.5.md)
- [Commits](sebastianbergmann/phpunit@7.5.20...9.5.3)

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -59,7 +59,7 @@
         "drupal/wysiwyg_template": "^2.1",
         "drush/drush": "^10.3",
         "phpoffice/phpspreadsheet": "1.17.1",
-        "phpunit/phpunit": "^7.5",
+        "phpunit/phpunit": "^9.5",
         "vlucas/phpdotenv": "^2.4",
         "webflo/drupal-finder": "^1.0.0",
         "webmozart/path-util": "^2.3"