release: Zephyr 4.0.0-rc2

Bump the version file for RC2.

Signed-off-by: Dan Kalowsky <dkalowsky@amperecomputing.com>
diff --git a/VERSION b/VERSION
index 1659ec4..939e2da 100644
--- a/VERSION
+++ b/VERSION
@@ -2,4 +2,4 @@
 VERSION_MINOR = 0
 PATCHLEVEL = 0
 VERSION_TWEAK = 0
-EXTRAVERSION = rc1
+EXTRAVERSION = rc2