MLECO-4072: update MLEK dependencies to 23.08

* version updates in cmakelists file
* update submodules to 23.08 versions
* updates to documentation - vela 3.9.0

Change-Id: I5e24d5729ecbd2289b04fcc845fb44f455ab38d5
Signed-off-by: Nina Drozd <nina.drozd@arm.com>
diff --git a/release_notes.txt b/release_notes.txt
index cc34c0a..7296739 100644
--- a/release_notes.txt
+++ b/release_notes.txt
@@ -1,3 +1,7 @@
+Changes in 23.08
+    * Support for 23.08 NPU components and dependencies (core-driver, core-platform, Vela 3.9.0, CMSIS, CMSIS-NN and TensorFlow Lite Micro).
+    * Update Python package requirements for compatibility reasons.
+
 Changes in 23.05
     * Support for 23.05 NPU components and dependencies (core-driver, core-platform, Vela 3.8.0, CMSIS, CMSIS-NN and TensorFlow Lite Micro).
     * Minor updates to CMSIS-pack dependencies.