太久没搞Jekyll的环境，构建的时候报错：

/usr/gem/gems/jekyll-4.2.2/lib/jekyll/commands/serve/servlet.rb:3:in `require': cannot load such fil/usr/gem/gems/jekyll-4.2.2/lib/jekyll/commands/serve/servlet.rb:3:in `require': cannot load such file -- webrick (LoadError)

原因是Webrick已从Ruby 3.0.0中删除，需要单独安装webrick:

bundle add webrick