Always use SSH checkouts in test jobs

This allows us to bypass Github rate-limits on anonymous checkouts.

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
Change-Id: I353ef36a955e29b9d7c06cad1e77755f8ddceed0
diff --git a/mbedtls-dockerfile-builder.yaml b/mbedtls-dockerfile-builder.yaml
index 1741ec8..2f614eb 100644
--- a/mbedtls-dockerfile-builder.yaml
+++ b/mbedtls-dockerfile-builder.yaml
@@ -11,9 +11,10 @@
                       checkout([
                           scm: [
                               $class: 'GitSCM',
-                              userRemoteConfigs: [
-                                  [url: MBED_TLS_TEST_REPO]
-                              ],
+                              userRemoteConfigs: [[
+                                  url: MBED_TLS_TEST_REPO,
+                                  credentialsId: mbedtls-github-ssh
+                              ]],
                               branches: [[name: MBED_TLS_TEST_BRANCH]],
                               extensions: [
                                   [$class: 'CloneOption', timeout: 60],
@@ -72,7 +73,7 @@
     name: mbedtls-dockerfile-builder
     parameters:
     - string:
-        default: https://github.com/Mbed-TLS/mbedtls-test.git
+        default: ssh://git@github.com/Mbed-TLS/mbedtls-test.git
         description: Enter mbed TLS test repo/fork
         name: MBED_TLS_TEST_REPO
         trim: 'false'