title: Composer update gives error phpunit/phpunit
body: <p>I recently installed php (8.1.7) and composer (2.3.7) and laravel 9;
  Now I am getting this error while running the command
  <code>composer update </code>
  on a laravel project, I searched a lot but couldn't find exact solution, all of them were not discussing the issue of phpunit/phpunit.</p>
  <p>The error looks like this:</p>
  <pre><code>
    Problem 1
      - phpunit/phpunit[6.0.0, ..., 6.5.14] require php ^7.0 -&gt; your php version (8.1.7) does not satisfy that requirement.
      - Root composer.json requires phpunit/phpunit ~6.0 -&gt; satisfiable by phpunit/phpunit[6.0.0, ..., 6.5.14].```
  </code></pre>