The approach in the article won’t work with Netlify because it relies on Apache .htaccess files, which Netlify doesn’t do.
What you could do in Netlify is manually compress the file with GZIP and then in the _headers file set favicon.ico to have Content-Encoding: gzip. The downside of this approach (besides being manual) is that any client which doesn’t support GZIP (which is probably a bad, old client, but still) won’t be able to use the file.