bump version to 19.4.3

Author: Flyingmana

app/Mage.php

@@ -215,7 +215,7 @@ public static function getOpenMageVersionInfo()
         return array(
             'major'     => '19',
             'minor'     => '4',
-            'patch'     => '2',
+            'patch'     => '3',
             'stability' => '', // beta,alpha,rc
             'number'    => '', // 1,2,3,0.3.7,x.7.z.92 @see https://semver.org/#spec-item-9
         );