release: Zephyr v3.6.0-rc3

Sets the version to v3.6.0-rc3.

Signed-off-by: Maureen Helm <maureen.helm@analog.com>
diff --git a/VERSION b/VERSION
index 0d8c7d4..be70f71 100644
--- a/VERSION
+++ b/VERSION
@@ -2,4 +2,4 @@
 VERSION_MINOR = 6
 PATCHLEVEL = 0
 VERSION_TWEAK = 0
-EXTRAVERSION = rc2
+EXTRAVERSION = rc3