feat: update mbedtls to version 3.6.2

Signed-off-by: Ryan Everett <ryan.everett@arm.com>
Change-Id: Ifadd318a0862c0af47bc606e6ea99cbec100b924
diff --git a/tf-a-main.yaml b/tf-a-main.yaml
index 676d200..d6fbe8e 100644
--- a/tf-a-main.yaml
+++ b/tf-a-main.yaml
@@ -44,7 +44,7 @@
             default: '+refs/heads/master:refs/remotes/origin/master'
         - string:
             name: MBEDTLS_URL
-            default: 'https://github.com/Mbed-TLS/mbedtls/archive/mbedtls-3.6.1.tar.gz'
+            default: 'https://github.com/Mbed-TLS/mbedtls/archive/mbedtls-3.6.2.tar.gz'
         - string:
             name: LAVA_RETRIES
             default: 2