$ brew changelog wget
Error: uninitialized constant YAML
/usr/local/Homebrew/Library/Taps/danielbayley/homebrew-changelog/lib/utils.rb:61:in `<top (required)>'
/usr/local/Homebrew/Library/Taps/danielbayley/homebrew-changelog/cmd/changelog.rb:8:in `require_relative'
/usr/local/Homebrew/Library/Taps/danielbayley/homebrew-changelog/cmd/changelog.rb:8:in `<top (required)>'
/usr/local/Homebrew/Library/Homebrew/extend/kernel.rb:10:in `require'
/usr/local/Homebrew/Library/Homebrew/extend/kernel.rb:10:in `require?'
/usr/local/Homebrew/Library/Homebrew/commands.rb:77:in `external_ruby_v2_cmd_path'
/usr/local/Homebrew/Library/Homebrew/brew.rb:93:in `<main>'