If following the approach described in #9 (comment), the generated HTML documentation could be hosted on a free service like Github Pages or ReadTheDocs. I personally like ReadTheDocs a lot, especially now that it can be configured to do unofficial builds automatically on pull requests as one of the status checks -- useful not only for confirming that you didn't break the docs build, but also for viewing the output to make sure all looks nice without having to clone the PR branch down and build it yourself locally. RTD also handles documentation versioning nicely so you can go back and view documentation for the previous versions of your package.
If following the approach described in #9 (comment), the generated HTML documentation could be hosted on a free service like Github Pages or ReadTheDocs. I personally like ReadTheDocs a lot, especially now that it can be configured to do unofficial builds automatically on pull requests as one of the status checks -- useful not only for confirming that you didn't break the docs build, but also for viewing the output to make sure all looks nice without having to clone the PR branch down and build it yourself locally. RTD also handles documentation versioning nicely so you can go back and view documentation for the previous versions of your package.