Update version of mbed TLS to v3.2.1

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: Ie81850ce8136a7303031f0dc50832bf412322281
diff --git a/tf-m-nightly-code-coverage.yaml b/tf-m-nightly-code-coverage.yaml
index 8112371..ebe1a2f 100644
--- a/tf-m-nightly-code-coverage.yaml
+++ b/tf-m-nightly-code-coverage.yaml
@@ -58,7 +58,7 @@
             For use when triggering with unmerged Gerrit changes.
       - string:
           name: 'MBEDTLS_VERSION'
-          default: 'mbedtls-3.1.0'
+          default: 'mbedtls-3.2.1'
       - string:
           name: 'MBEDTLS_URL'
           default: 'https://git.trustedfirmware.org/mirror/mbed-tls.git'