Merge pull request #117 from mmarynich/feature/phpcs-err-output

Phpcs error message fix

Author: bruli

src/PhpGitHooks/Module/PhpCs/Infrastructure/Tool/PhpCsToolProcessor.php

@@ -64,12 +64,16 @@ private function execute($file, $standard, $ignore)
     /**
      * @param Process $process
      *
-     * @return string
+     * @return null|string
+     *
+     * @throws \Symfony\Component\Process\Exception\LogicException
      */
     private function setErrors(Process $process)
     {
         if (false === $process->isSuccessful()) {
-            return $process->getErrorOutput();
+            return $process->getErrorOutput() ?: $process->getOutput();
         }
+
+        return null;
     }
 }