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>
diff --git a/docs/getting_started/prerequisites.rst b/docs/getting_started/prerequisites.rst
index c414b1f..32c2b39 100644
--- a/docs/getting_started/prerequisites.rst
+++ b/docs/getting_started/prerequisites.rst
@@ -31,7 +31,7 @@
 Clang/LLVM               18.1.8
 Device Tree Compiler     1.6.1
 GNU make                 3.81
-mbed TLS\ [#f1]_         3.6.1
+mbed TLS\ [#f1]_         3.6.2
 Node.js [#f2]_           16
 OpenSSL                  1.0.0
 Poetry                   1.3.2