Add workflow for deploying a demo to GitHub Pages

[jtpio]

Fixes #4

[jtpio]

Looking good trying the built archive locally:

[jtpio]

Merging to see if that works on the real GitHub pages deployment.

[ianthomas23]

Thanks for this!

[ianthomas23]

To clarify, if we make changes to cockle then for them to appear in the github pages deployment we need a new release of cockle and a PR or push to main branch here?

[jtpio]

Yes we need to update the dependency in package.json (and update the yarn.lock):

terminal/package.json

Line 63 in 2f20f35

"@jupyterlite/cockle": "^0.0.3",

And open a PR here and merge it into main.