lts-v2.12: use mbedtls v3.6.3

Change-Id: Ib109ce7e75fd190e54542818c520186fe10e719f
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/tf-a-lts2.12-main.yaml b/tf-a-lts2.12-main.yaml
index 250ead8..64f4778 100644
--- a/tf-a-lts2.12-main.yaml
+++ b/tf-a-lts2.12-main.yaml
@@ -57,7 +57,7 @@
             tf-a-job-configs refspec to use. The master branch is used by default.
       - string:
           name: MBEDTLS_URL
-          default: 'https://github.com/Mbed-TLS/mbedtls/archive/mbedtls-3.6.2.tar.gz'
+          default: 'https://github.com/Mbed-TLS/mbedtls/archive/mbedtls-3.6.3.tar.gz'
       - bool:
           name: FORCE_TO_BUILD
           default: false