* We now use GitHub Actions instead of a private Drone which is great
for OSS build transparency, but one drawback to that change is that
we no longer auto-deploy matchbox to internal Poseidon Labs infra
* We don't want public workflows for deploys to our private infra
* Add a publish workflow that uses the mkdocs-pages re-usable GitHub
Workflow when the `release-docs` branch is updated
* Build the docs site with mkdocs and publish to GitHub Pages
* Migrate from the internal Drone server using a GitHub Workflow
to perform the multi-arch container image build
* Use self-hosted GitHub runners on ARM64 to perform the ARM64
build step faster that QEMU/KVM emulation
* Mandate approval for all workflow runs from outside contributors
since the builds use push credentials and partially run internally
* Default branch was renamed from master to main
* Internal build and publishing workflows were unaffected,
the GitHub Action is just for public contribution vetting