Fix incorrect hard-coded value for PendingIntentFlags.Mutable

Author: pshbot

UsbSerialForAndroid/Extensions/UsbManagerExtensions.cs

@@ -33,7 +33,7 @@ public static Task<bool> RequestPermissionAsync(this UsbManager manager, UsbDevi
 #if NET6_0_OR_GREATER
             PendingIntentFlags pendingIntentFlags = Build.VERSION.SdkInt >= BuildVersionCodes.S ? PendingIntentFlags.Mutable : 0;
 #else
-            PendingIntentFlags pendingIntentFlags = Build.VERSION.SdkInt >= (BuildVersionCodes)31 ? (PendingIntentFlags).33554432 : 0;
+            PendingIntentFlags pendingIntentFlags = Build.VERSION.SdkInt >= (BuildVersionCodes)31 ? (PendingIntentFlags)33554432 : 0;
 #endif
 
             var intent = PendingIntent.GetBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), pendingIntentFlags);