docs(prerequisites): update mbedtls to version 3.6.2

This new update to the LTS branch of MbedTLS provides
the fix for a buffer underrun vulnerability. TF-A does
not use the previously vulnerable functions
`mbedtls_pk_write_key_der` or `mbedtls_pk_write_key_pem`.
Full patch notes to this MbedTLS update can be found at
https://github.com/Mbed-TLS/mbedtls/releases/tag/mbedtls-3.6.2.

Change-Id: Ibc4a8712c92019648fe0e75390cd3540d86b735d
Signed-off-by: Ryan Everett <ryan.everett@arm.com>
(cherry picked from commit 95037029a7b9da875ae0f10d581c2568ca7e05f6)
diff --git a/docs/getting_started/prerequisites.rst b/docs/getting_started/prerequisites.rst
index ab28ede..51723ea 100644
--- a/docs/getting_started/prerequisites.rst
+++ b/docs/getting_started/prerequisites.rst
@@ -77,7 +77,7 @@
 The following libraries are required for Trusted Board Boot and Measured Boot
 support:
 
-- mbed TLS == 3.6.1 (tag: ``mbedtls-3.6.1``)
+- mbed TLS == 3.6.2 (tag: ``mbedtls-3.6.2``)
 
 These tools are optional:
 
@@ -184,7 +184,7 @@
 
 --------------
 
-*Copyright (c) 2021-2023, Arm Limited. All rights reserved.*
+*Copyright (c) 2021-2025, Arm Limited. All rights reserved.*
 
 .. _Arm Developer website: https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/downloads
 .. _Gerrit Code Review: https://www.gerritcodereview.com/