GitLab publish to NPM

.gitlab-ci.yml

image: node:12
cache:
  paths:
    - node_modules/
stages:
  - setup
  - test
  - deploy

install:
  stage: setup
  script:
    - npm install
  after_script:
    - npm run postinstall

test:
  stage: test
  script:
    - npm run test
    
publish:
  stage: deploy
  only:
    - tags
#     - triggers
  except:
    - branches
  before_script:
#     - npm config set '//registry.npmjs.org/:_authToken' "${NPM_TOKEN}"
    - echo "//registry.npmjs.org/:_authToken=${NPM_TOKEN}">.npmrc
  script:
    - npm publish