GitHub actions for deploying to gh-pages

[manastalukdar]

Steps

• Add steps in existing main.yml to deploy to gh-pages.
• When caching artifacts across workflows is implemented
  • There will have to be at least 2 workflows:
    • Build, test.
    • Deploy
    • A third may be needed depending on whether workflows have support for setting dependencies internally, or workflow dependencies would have to be wired up using a wrapper workflow.
  • Cache necessary output from build test workflow and use that in the deployment workflow.
• Finally update workflows in the template-repo.

Useful

• https://github.com/peaceiris/actions-gh-pages
• https://github.com/JamesIves/github-pages-deploy-action
• https://github.com/actions/cache