Corrects Zephyr include files for current versions of Zephyr (#2881)

This fixes bug #2880.  Zephyr 3.2 made changes to how headers are reference (see [release notes](https://docs.zephyrproject.org/latest/releases/release-notes-3.2.html)).  Work item [49578](https://github.com/zephyrproject-rtos/zephyr/issues/49578) deprecated the old headers names.
The current WAMR codebase references these old headers, thus causing compile errors with
current versions of Zephyr.

This update adds #ifdefs around the header names.  With this change, compiling with Zephyr 3.2.0
and above will use the new header files.  Prior versions will use the existing code.

core/app-mgr/app-manager/platform/zephyr/app_mgr_zephyr.c

@@ -6,8 +6,14 @@
 #include "app_manager.h"
 #include "bh_platform.h"
 #include <autoconf.h>
+
+#if KERNEL_VERSION_NUMBER < 0x030200 /* version 3.2.0 */
 #include <zephyr.h>
 #include <kernel.h>
+#else
+#include <zephyr/kernel.h>
+#endif
+
 #if 0
 #include <sigverify.h>
 #endif