Use firstObject instead [0] when accessing the first element in the windows array

firstObject returns nil if there is none. Using [0] or objectAtIndex:0 will crash if there is no object there

Author: jnavarrom

CHANGELOG.md

@@ -1,3 +1,6 @@
+# 3.9.4
+* Avoid a crash in iOS 13 accessing the first object of the windows.
+
 # 3.9.3
 * Fixed a crash in demo project.
 * Removed unused string.

LTHPasscodeViewController/LTHPasscodeViewController.m

@@ -50,7 +50,7 @@
 #ifdef LTH_IS_APP_EXTENSION
 #define LTHMainWindow [UIApplication sharedApplication].keyWindow
 #else
-#define LTHMainWindow [UIApplication sharedApplication].windows[0]
+#define LTHMainWindow [UIApplication sharedApplication].windows.firstObject
 #endif
 
 @interface LTHPasscodeViewController () <UITextFieldDelegate>