Update version number to 10.4.0 (#153)

diff --git a/include/task.h b/include/task.h
index f51dbd4..58ffd1f 100644
--- a/include/task.h
+++ b/include/task.h
@@ -1,5 +1,5 @@
 /*
- * FreeRTOS Kernel V10.3.1
+ * FreeRTOS Kernel V10.4.0
  * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of
@@ -44,10 +44,10 @@
 * MACROS AND DEFINITIONS
 *----------------------------------------------------------*/
 
-#define tskKERNEL_VERSION_NUMBER       "V10.3.1"
+#define tskKERNEL_VERSION_NUMBER       "V10.4.0"
 #define tskKERNEL_VERSION_MAJOR        10
-#define tskKERNEL_VERSION_MINOR        3
-#define tskKERNEL_VERSION_BUILD        1
+#define tskKERNEL_VERSION_MINOR        4
+#define tskKERNEL_VERSION_BUILD        0
 
 /* MPU region parameters passed in ulParameters
  * of MemoryRegion_t struct. */