Fixed Android ZipFile function so that it successfuly runs on Linux OS systems

Assets/AppCenter/Editor/AndroidLibraryHelper.cs

@@ -27,7 +27,7 @@ public static class AndroidLibraryHelper
                 .ToString();
             processName = "cmd";
         }
-        else if (Application.platform == RuntimePlatform.OSXEditor)
+        else if (Application.platform == RuntimePlatform.OSXEditor || Application.platform == RuntimePlatform.LinuxEditor)
         {
             args = stringBuilder
                 .Append("-c \"cd ")