Add public keyword to methods

[MAILPOET-2413]

tests/integration/Cron/Workers/SimpleWorkerMockImplementation.php

@@ -6,7 +6,7 @@ class SimpleWorkerMockImplementation extends SimpleWorker {
   const TASK_TYPE = 'mock_simple_worker';
   const SUPPORT_MULTIPLE_INSTANCES = false;
 
-  function init() {
+  public function init() {
     // to be mocked
   }
 }