Create a class for Repo under test

src/org/moodle/ci/Target.groovy

+package org.moodle.ci;
+
+class Target {
+    protected String url
+
+    protected String credentialsId
+
+    protected String branch
+}

src/org/moodle/ci/repositories/Repository.groovy

@@ -3,7 +3,13 @@ package org.moodle.ci.repositories;
 class Repository {
     protected String url
 
+    protected String credentialsId
+
     def getUrl() {
         return url
     }
+
+    def getCredential() {
+        return credentialsId
+    }
 }

src/org/moodle/ci/repositories/Security.groovy

+package org.moodle.ci.repositories;
+
+class Security extends Repository {
+    Security() {
+        this.url = "git@git.in.moodle.com:integration/security.git"
+        this.credentialsId = 'security'
+    }
+}

vars/runTask.groovy

-def call(String task, String branch, String repo, String phpversion, String database, Boolean notify) {
+def call(String task, org.moodle.ci.Target Target, String phpversion, String database, Boolean notify) {
     pipeline {
         agent {
             label 'docker'
@@ -19,7 +19,7 @@ def call(String task, String branch, String repo, String phpversion, String data
                             $class: 'GitSCM',
                             branches: [
                                 [
-                                    name: "${branch}"
+                                    name: "${Target.branch}"
                                 ]
                             ],
                             doGenerateSubmoduleConfigurations: false,
@@ -39,9 +39,12 @@ def call(String task, String branch, String repo, String phpversion, String data
                             submoduleCfg: [],
                             userRemoteConfigs: [
                                 [
-                                    url: "${repo}"
-                                ]
+                                    url: "${Target.repo}",
+                                    credentialsId: "${Target.credentialsId}"
+                                ],
+                                [
                             ]
+                            userRemoteConfigs: [[credentialsId: 'security', url: 'a']]])
                         ]
                     )
                 }