doc: release-notes: mention civetweb module removal

Add a line to mention the removed civeteweb module and code.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
diff --git a/doc/releases/release-notes-3.2.rst b/doc/releases/release-notes-3.2.rst
index 6782ef3..1065ae6 100644
--- a/doc/releases/release-notes-3.2.rst
+++ b/doc/releases/release-notes-3.2.rst
@@ -106,6 +106,8 @@
 * Removed support for configuring the CAN-FD maximum DLC value via Kconfig
   ``CONFIG_CANFD_MAX_DLC``.
 
+* Removed deprecated civetweb module and the associated support code and samples.
+
 Deprecated in this release
 ==========================