Remove obsolete versioning information

Author: Greg Bowler

README.md

@@ -9,9 +9,7 @@ There are unit tests stored within the `test` directory, along with a `phpunit.x
 
 The file at `.github/workflows/ci.yml` shows how to use [php-actions/phpunit][action-link] - take note of the `uses: php-actions/phpunit@v9` line.
 
-Versions of PHPUnit and all options are available to configure. Please see the [php-actions/phpunit documentation][action-link] for more information!
-
-Please note **the version number of the Github Action must match your composer.json major version number**. For example, if your composer.json requires `phpunit/phpunit 8.5.8`, you must use `php-actions/phpunit@v8`, as major versions of PHPUnit are incompatible with each other.   
+Versions of PHPUnit and all options are available to configure. Please see the [php-actions/phpunit documentation][action-link] for more information! 
 
 ***