Upgrade downgraded PHPUnit

Author: ondrejmirtes

.github/workflows/build.yml

@@ -39,7 +39,7 @@ jobs:
 
       - name: "Downgrade PHPUnit"
         if: matrix.php-version == '7.2' || matrix.php-version == '7.3'
-        run: "composer require --dev phpunit/phpunit:^7.5.20 --no-update --update-with-dependencies"
+        run: "composer require --dev phpunit/phpunit:^8.5.31 --no-update --update-with-dependencies"
 
       - name: "Install dependencies"
         run: "composer install --no-interaction --no-progress"
@@ -104,7 +104,7 @@ jobs:
 
       - name: "Downgrade PHPUnit"
         if: matrix.php-version == '7.2' || matrix.php-version == '7.3'
-        run: "composer require --dev phpunit/phpunit:^7.5.20 --no-update --update-with-dependencies"
+        run: "composer require --dev phpunit/phpunit:^8.5.31 --no-update --update-with-dependencies"
 
       - name: "Install lowest dependencies"
         if: ${{ matrix.dependencies == 'lowest' }}
@@ -145,7 +145,7 @@ jobs:
 
       - name: "Downgrade PHPUnit"
         if: matrix.php-version == '7.2' || matrix.php-version == '7.3'
-        run: "composer require --dev phpunit/phpunit:^7.5.20 --no-update --update-with-dependencies"
+        run: "composer require --dev phpunit/phpunit:^8.5.31 --no-update --update-with-dependencies"
 
       - name: "Install dependencies"
         run: "composer update --no-interaction --no-progress"