feat: update MbedTLS URL to v3.6.1 for LTS v2.8

Change-Id: Ibc62846978218719db8330ea41590c66cf9ea0af
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/tf-a-lts2.8-builder.yaml b/tf-a-lts2.8-builder.yaml
index d6510f4..d70eaa2 100644
--- a/tf-a-lts2.8-builder.yaml
+++ b/tf-a-lts2.8-builder.yaml
@@ -53,7 +53,7 @@
             default: 'http://releases.linaro.org/openembedded/aarch64/17.01/linaro-image-minimal-genericarmv8-20170127-888.rootfs.tar.gz'
         - string:
             name: MBEDTLS_URL
-            default: 'https://github.com/Mbed-TLS/mbedtls/archive/mbedtls-3.6.0.tar.gz'
+            default: 'https://github.com/Mbed-TLS/mbedtls/archive/mbedtls-3.6.1.tar.gz'
         - string:
             name: GERRIT_PATCHSET_NUMBER
             default: ''