This function auto-detects the location of your package logo (with the name
logo.svg (recommended format) or logo.png) and runs it through the
https://realfavicongenerator.net API to build a complete set of favicons
with different sizes, as needed for modern web usage.
build_favicon(pkg = ".")Path to package.
You only need to run the function once. The favicon set will be stored in
pkgdown/favicon and copied by init_site() to the relevant location when
the website is rebuilt.