Check with older PHPStan GHA action

Author: Michael Vasseur

.github/workflows/phpstan.yml

@@ -15,7 +15,7 @@ jobs:
         run: .github/jobs/composer_setup.sh
       - name: Show the phpstan version
         run: webapp/vendor/phpstan/phpstan/phpstan --version
-      - uses: php-actions/phpstan@v3
+      - uses: php-actions/phpstan@v3.0.0
         with:
           configuration: webapp/phpstan.dist.neon
           path: webapp/src webapp/tests