change(jenkins): added yarn policy for storybook building

latest version crashes with workspace not created for some dependency from react-countup

Jenkinsfile

@@ -280,7 +280,7 @@ pipeline {
                   sh '''git clone --branch develop https://github.com/eea/volto-kitkat-frontend.git'''
 
                   withCredentials([string(credentialsId: 'volto-kitkat-frontend-chromatica', variable: 'CHROMATICA_TOKEN')]) {
-                    def RETURN_STATUS = sh(script: '''cd volto-kitkat-frontend; npm install -g mrs-developer chromatic; yarn cache clean; yarn develop; cd src/addons/$GIT_NAME; git fetch origin pull/${CHANGE_ID}/head:PR-${CHANGE_ID}; git checkout PR-${CHANGE_ID}; cd ../../..; yarn install; yarn build-storybook; npx chromatic --no-interactive --force-rebuild  --project-token=$CHROMATICA_TOKEN | tee chromatic.log; cd ..''', returnStatus: true)
+                    def RETURN_STATUS = sh(script: '''cd volto-kitkat-frontend; npm install -g mrs-developer chromatic; yarn cache clean; yarn develop; cd src/addons/$GIT_NAME; git fetch origin pull/${CHANGE_ID}/head:PR-${CHANGE_ID}; git checkout PR-${CHANGE_ID}; cd ../../..; yarn policies set-version 1.18.0; yarn install; yarn build-storybook; npx chromatic --no-interactive --force-rebuild  --project-token=$CHROMATICA_TOKEN | tee chromatic.log; cd ..''', returnStatus: true)
                     if ( RETURN_STATUS == 0 ) {
                       def STORY_URL = sh(script: '''grep "View your Storybook" volto-kitkat-frontend/chromatic.log | sed "s/.*https/https/" ''', returnStdout: true).trim()
                       pullRequest.comment("### :heavy_check_mark: Storybook:\n${STORY_URL}\n\n:rocket: @${GITHUB_COMMENT_AUTHOR}")