Revert "Install PHP 8.1 dependencies ignoring php req"

This reverts commit a9d2cd2.

Author: GrahamCampbell

.github/workflows/tests.yml

@@ -33,15 +33,6 @@ jobs:
           timeout_minutes: 5
           max_attempts: 5
           command: composer update --no-interaction --no-progress
-        if: "matrix.php < 8.1"
-
-      - name: Install PHP 8.1 Dependencies
-        uses: nick-invision/retry@v1
-        with:
-          timeout_minutes: 5
-          max_attempts: 5
-          command: composer update --no-interaction --no-progress --ignore-platform-req=php
-        if: "matrix.php >= 8.1"
 
       - name: Execute PHPUnit
         run: vendor/bin/phpunit