doc: releases: migration-guide: 4.2: mention NEORV32 version bump

Mention the move to support v1.11.1 of the NEORV32 RISC-V processor.

Signed-off-by: Henrik Brix Andersen <[email protected]>

Author: henrikbrixandersen

doc/releases/migration-guide-4.2.rst

@@ -32,6 +32,8 @@ Boards
 * The config option :kconfig:option:`CONFIG_NATIVE_POSIX_SLOWDOWN_TO_REAL_TIME` has been deprecated
   in favor of :kconfig:option:`CONFIG_NATIVE_SIM_SLOWDOWN_TO_REAL_TIME`.
 
+* Zephyr now supports version 1.11.1 of the :zephyr:board:`neorv32`.
+
 Device Drivers and Devicetree
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