Update Jenkinsfile

Jenkinsfile

@@ -77,7 +77,7 @@ pipeline {
                             // builds.each{ k, v -> v.push(k) } <- not used anymore
 
                             // the following command needs to be run first on a new node, but not after that
-                            sh 'docker buildx create --use --name multiarch --append'
+                            // sh 'docker buildx create --use --name multiarch --append'
                             EXERCISE_FOLDERS.each { exercise, folder ->
                                 // old non multi-arch way
                                 // def build = docker.build("${maintainer}/${imagename}:${exercise}-${tag}", "--no-cache --pull --build-arg VERSION_TAG=${tag} ${folder}")