Jupyter Releaser setup

[jtpio]

Keeping track of the list of tasks:

• [x] Create the GitHub app for the QuantStack org
• [x] Add workflows: https://github.com/QuantStack/yjs-widgets/pull/16
• [x] Create the release environment and add APP_ID and APP_PRIVATE_KEY
• [x] Add trusted publisher to the PyPI repo: https://pypi.org/project/yjs-widgets/
• [x] Add NPM_TOKEN to the secrets (org secret)
• [x] Make sure the npm package has a public publish config: https://jupyter-releaser.readthedocs.io/en/latest/faq/index.html#failed-to-publish-a-package-to-npm

https://github.com/QuantStack/yjs-widgets/blob/5010afdcec88fda5589b4ac677f3e952d40d815b/package.json#L94-L96

• [x] Add quantstack-bot as a contributor to the package on npm: https://www.npmjs.com/~quantstack-bot - https://www.npmjs.com/package/yjs-widgets
• [x] Init CHANGELOG.md: https://github.com/QuantStack/yjs-widgets/pull/18

[davidbrochart]

I just released v0.3.8 with the jupyter-releaser, thanks!