Fix wxGetWinVersion() for Windows 10

Check for Windows 10 was implemented as check for version 6.4 but the final version of Windows 10 actually returns 10.0.

src/msw/utils.cpp

@@ -1391,10 +1391,11 @@ wxWinVersion wxGetWinVersion()
                         case 3:
                             return wxWinVersion_8_1;
 
-                        case 4:
-                            return wxWinVersion_10;
-					}
+                    }
                     break;
+                    
+                case 10:
+                    return wxWinVersion_10;
             }
         default:
             // Do nothing just to silence GCC warning