Generates DocC documentation from Swift Bitcoin's repo and deploy to /docs path of the organization's website.
Because it's simple enough to checkout Repo B (e.g. swift-bitcoin repo) from a GitHub Action running on Repo A (e.g. this repo) and deploy the generated docs to Repo A's GitHub Pages URL while it is not at all possible to run an Action directly on Repo B and have it deploy the docs artifacts to a different repo's Pages URL (or to the organization's Pages URL).
Having a standalone docs repo with Pages on will also create the subfolder needed (in this case docs) to host the documentation pages generated independently from the main site and blog.