AUTHORS: add FeniksFire. Again

Let's hope Warmonger won't remove him on merge ;-)

AUTHORS

@@ -58,5 +58,8 @@ Arseniy Shestakov aka SXX,      <[email protected]>
 Vadim Markovtsev, <[email protected]>
    * resolving problems with macOS, bug fixes
 
+Michał Kalinowski, <[email protected]>
+   * refactoring code
+
 Dydzio, <[email protected]>
    * Small features, improvements and bug fixes in all VCMI parts