- cd js:
    - Update version in package.json (via: python devtools/update_versions.py [version])
    - npm install && npm publish # to publish nglview-js-widgets for html embeding.
    - npm copy:labextension # to copy labextension files to nglview/labextension
- Update version in /nglview/_frontend.py
- Commit the change and push to master
- Create a release tag in github
- git fetch origin && git checkout <tag-number>
- PYTHONPATH=`pwd` ./devtools/release.py
- twine upload ./dist/<package>
