Use Github Actions to build and deploy the website

[leouieda]

Replaces TravisCI and doctr. It's a lot simpler to set up and actually
runs faster (though that's not a big issue here).

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/gmt/website/gzecg6djv
✅ Preview: https://website-git-actions.gmt.vercel.app

[leouieda]

I was experimenting with Github Actions a bit and decided to try this as a test. It worked perfectly for my own website so porting it here as well. Setup was actually pretty straight forward. I had to setup deploy keys since we need to push to a different repository but the instructions here were easy to follow: https://github.com/peaceiris/actions-gh-pages#%EF%B8%8F-create-ssh-deploy-key

This might work for the project docs as well with some modification since we need to maintain the older versions of the docs in the gh-pages branch.

[seisman]

I also find github actions easier to use and understand.

Recently, @weiji14 and I also migrated most of the CI jobs of the PyGMT project from Azure Pipelines to GitHub Actions.

[weiji14]

Yeah, there was a lot of work doing the CI migration (especially with the cache!) but I think it's worth it, I much prefer viewing the logs on Github than Azure Pipelines (though technically they're both Azure according to this).

[leouieda]

I saw that (going through my notifications is was what made me look into this actually). Thanks for doing all of that! I’m going to experiment on a test project with the docs and PyPI deployments.