use latest mbedtls v3.6.3

Change-Id: I92fc728e301c256158d5a39087f80c40b857f1fa
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
diff --git a/tf-a-gerrit-tforg-l1.yaml b/tf-a-gerrit-tforg-l1.yaml
index a826b5a..cd2d7e2 100644
--- a/tf-a-gerrit-tforg-l1.yaml
+++ b/tf-a-gerrit-tforg-l1.yaml
@@ -58,7 +58,7 @@
               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'
         - string:
             name: SHARE_FOLDER
             default: '/srv/shared/${JOB_NAME}/${BUILD_NUMBER}'