the code is in the master branch.
you want to deploy the dist folder from build to the gh-pages branch

.travis.yml

language: node_js
node_js: stable

install: npm install
script: npm run build

notifications:
  email: false

deploy:
  provider: pages
  skip_cleanup: true
  local-dir: dist
  github_token: $GITHUB_TOKEN -sharp Set in travis-ci.org dashboard
  on:
    branch: gh-pages

error prompt:

 DONE  Build complete. The dist directory is ready to be deployed.
      
The command "npm run build" exited with 0.
Skipping a deployment with the pages provider because this branch is not permitted

Done. Your build exited with 0.

it seems that I have a misunderstanding of on
, but it is still the same mistake after changing it to the following

  on:
    branch: master