TO DEPLOY TO GITHUB PAGES:
npm run deploy
That should also run predeploy script in package.json which I have also configured to add the CNAME directory to dist/. Ensure it does that or the custom domain won't work properly.
This process uses the gh-pages package. In Settings -> Pages on Github, the branch to deploy needs to be gh-pages, folder /. This package takes the dist/ folder that gets built and pushes it to that branch to keep the main branch clean of all the build stuff.