Update phpstan version

Author: Seldaek

.github/workflows/phpstan.yml

@@ -30,5 +30,5 @@ jobs:
 
       - name: Run PHPStan
         run: |
-          composer require --dev phpstan/phpstan:^0.12.93 marc-mabe/php-enum-phpstan ${{ env.COMPOSER_FLAGS }}
+          composer require --dev phpstan/phpstan:^1.5 marc-mabe/php-enum-phpstan ${{ env.COMPOSER_FLAGS }}
           vendor/bin/phpstan analyse