Try and fix phpstan

.github/workflows/phpstan.yml

@@ -46,12 +46,10 @@ jobs:
           key: "php-${{ matrix.php-version }}-symfony-php-unit-version-${{ env.SYMFONY_PHPUNIT_VERSION }}-${{ hashFiles('**/composer.lock') }}"
           restore-keys: "php-${{ matrix.php-version }}-symfony-php-unit-version-${{ env.SYMFONY_PHPUNIT_VERSION }}"
 
-      - name: "Install dependencies from composer.lock using composer binary provided by system"
-        run: "composer install ${{ env.COMPOSER_FLAGS }}"
+      - name: "Install highest dependencies from composer.json using composer binary provided by system"
+        run: "composer config platform --unset && composer update ${{ env.COMPOSER_FLAGS }}"
 
       - name: Run PHPStan
         run: |
-          bin/composer config platform --unset
-          bin/composer require --dev phpstan/phpstan:^0.12 phpunit/phpunit:^7.5 --no-update
-          bin/composer update phpstan/* phpunit/* sebastian/* --with-all-dependencies
+          bin/composer require --dev phpstan/phpstan:^0.12 phpunit/phpunit:^7.5 --with-all-dependencies
           vendor/bin/phpstan analyse --configuration=phpstan/config.neon