adds quote do cred ID

Jenkinsfile

@@ -27,7 +27,7 @@ def runOneRegression(String suite, String preset, String simulatorPath) {
 def resolveImageCommit(String image) {
 
   withCredentials([usernamePassword(
-    credentialsId: gitea-jenkins,
+    credentialsId: 'gitea-jenkins',
     usernameVariable: 'REGISTRY_USER',
     passwordVariable: 'REGISTRY_PASS'
   )]) {