runTask: Maybe more is better

vars/runTask.groovy

@@ -52,7 +52,7 @@ def call(String task, String branch, String repo, String phpversion, String data
                 steps {
                     script {
                         moodleversion = sh (
-                            script: 'grep "$branch" moodle/version.php | sed "s/^[^\']*\'\\([^\']*\\).*\$/\\1/"',
+                            script: 'grep "\\$branch" moodle/version.php | sed "s/^[^\']*\'\\([^\']*\\).*\$/\\1/"',
                             returnStdout: true
                         ).trim()
                         runner = "${env.PATHTORUNNER}/${moodleversion}"