switch to yarn

Jenkinsfile

@@ -15,7 +15,7 @@ pipeline {
         stage('Setup') {
             steps {
                 echo 'Setting up test environment'
-                sh 'npm ci'
+                sh 'yarn --frozen-lockfile'
                 sh 'nodejs jenkins.js ${VERSION}'
                 script {
                     currentBuild.displayName = env.VERSION
@@ -29,7 +29,7 @@ pipeline {
                 publish = sh script: "git log -1 | grep '\\[no publish\\]'", returnStatus: true
                 if (publish != 0) {
                   echo 'Deploying'
-                  sh 'npm publish'   
+                  sh 'yarn publish'   
                 } else {
                   echo 'Build successful, Commit not marked for deploying'
                   currentBuild.result = "UNSTABLE"