runTask: Be shallow

vars/runTask.groovy

@@ -28,7 +28,7 @@ def call(String task, String branch, String repo, String phpversion, String data
                                     depth: 0,
                                     noTags: false,
                                     reference: "${env.HOME}/cache/integration.git",
-                                    shallow: false
+                                    shallow: true
                                 ],
                                 [
                                     $class: 'RelativeTargetDirectory',