Similar to PHPUnit, trigger PHPStan version which is actually in the project

Author: Macavity

.github/workflows/php.yml

@@ -37,9 +37,5 @@ jobs:
       - name: Run PHPUnit
         run: composer run phpunit
 
-      - name: Run PHPStan
-        uses: docker://oskarstark/phpstan-ga
-        env:
-          REQUIRE_DEV: true
-        with:
-          args: analyse src/ --level=6
+      - name: Run PHPUnit
+        run: composer run phpstan