chore(deps): update dependency mbed-tls/mbedtls to v4

Author: openvpn-inc-ci

.github/workflows/build.yaml

@@ -404,7 +404,7 @@ jobs:
           submodules: true
           # versioning=semver-coerced
           repository: Mbed-TLS/mbedtls
-          ref: v3.6.4
+          ref: v4.0.0
       - name: "mbedtls: make no_test"
         run: make -j3 no_test SHARED=1
         working-directory: mbedtls