Fix: Adjust usage documentation

README.md

@@ -40,7 +40,7 @@ Download `phpunit-slow-test-detector.phar` from the [latest release](https://git
 
 ### Bootstrapping the extension as a `composer` package
 
-To bootstrap the extension as a `composer` package when using `phpunit/phpunit:^10.4.0`, adjust your `phpunit.xml` configuration file and configure the [`extensions` element](https://docs.phpunit.de/en/10.4/configuration.html#the-extensions-element):
+To bootstrap the extension as a `composer` package when using `phpunit/phpunit:^8.5.14` or `phpunit/phpunit:^9.6.0`, adjust your `phpunit.xml` configuration file and configure the [`extensions` element](https://docs.phpunit.de/en/9.6/configuration.html#the-extensions-element):
 
 ```diff
  <phpunit
@@ -49,7 +49,7 @@ To bootstrap the extension as a `composer` package when using `phpunit/phpunit:^
      bootstrap="vendor/autoload.php"
  >
 +    <extensions>
-+        <bootstrap class="Ergebnis\PHPUnit\SlowTestDetector\Extension"/>
++        <extension class="Ergebnis\PHPUnit\SlowTestDetector\Extension"/>
 +    </extensions>
      <testsuites>
          <testsuite name="unit">
@@ -59,7 +59,7 @@ To bootstrap the extension as a `composer` package when using `phpunit/phpunit:^
  </phpunit>
 ```
 
-To bootstrap the extension as a `composer` package when using `phpunit/phpunit:^9.6.0`, adjust your `phpunit.xml` configuration file and configure the [`extensions` element](https://docs.phpunit.de/en/9.6/configuration.html#the-extensions-element):
+To bootstrap the extension as a `composer` package when using `phpunit/phpunit:^10.4.0`, adjust your `phpunit.xml` configuration file and configure the [`extensions` element](https://docs.phpunit.de/en/10.4/configuration.html#the-extensions-element):
 
 ```diff
  <phpunit
@@ -68,7 +68,7 @@ To bootstrap the extension as a `composer` package when using `phpunit/phpunit:^
      bootstrap="vendor/autoload.php"
  >
 +    <extensions>
-+        <extension class="Ergebnis\PHPUnit\SlowTestDetector\Extension"/>
++        <bootstrap class="Ergebnis\PHPUnit\SlowTestDetector\Extension"/>
 +    </extensions>
      <testsuites>
          <testsuite name="unit">