feat: add altdoc (#399)

README.md

@@ -138,6 +138,7 @@ Contributions of any kind are welcome, just follow the [guidelines](.github/CONT
 - [matrix BOT](https://github.com/rgomez90/matrix-bot) - A little bot for the [matrix-network](https://matrix.org/) that listens for some Quarto files and returns the PDF into the matrix channel.
 - [babelquarto](https://docs.ropensci.org/babelquarto/) - R package to help set up, and render, multilingual Quarto books (see also [babeldown](https://docs.ropensci.org/babeldown/articles/quarto.html)).
 - [quartodoc](https://github.com/machow/quartodoc) - A Python module that lets you quickly generate Python package API reference documentation using Markdown and Quarto.
+- [altdoc](https://github.com/etiennebacher/altdoc) - Alternative to pkgdown to document R packages.
 
 ## Continuous integration / Continuous deployment