npm deploy broken

[ianhi]

Describe the issue

in the deploy action the npm authentication seems to be broken: https://github.com/matplotlib/ipympl/runs/5243522626?check_suite_focus=true

npm ERR! code ENEEDAUTH
npm ERR! need auth This command requires you to be logged in to https://registry.npmjs.org/
npm ERR! need auth You need to authorize this machine using `npm adduser`

This isn't important for 0.8.8 because we didn't bump the js version, but this will matter for the next one.