Use oga instead of nokogiri

Dockerfile

@@ -1,5 +1,5 @@
 FROM ruby:3-alpine
-RUN apk add --no-cache ruby-bundler build-base libxml2-dev libxslt-dev
+RUN apk add --no-cache make gcc libc-dev
 RUN echo -e "#!/bin/sh\ncd /nanoleaf;./main.rb >> /var/log/nanoleaf" > /etc/periodic/15min/nanoleaf
 RUN chmod +x /etc/periodic/15min/nanoleaf
 RUN adduser -DHu 1001 nanoleaf
@@ -11,6 +11,5 @@ COPY --chown=1001 ["main.rb", "Gemfile", "effect.json", "/nanoleaf/"]
 ENV HOME="/tmp/"
 ENV GEM_HOME="/nanoleaf/vendor/bundle"
 ENV PATH $GEM_HOME/bin:$GEM_HOME/gems/bin:$PATH
-RUN bundle config build.nokogiri --use-system-libraries
 RUN bundle install
 CMD ./main.rb >> /var/log/nanoleaf & tail -F /var/log/nanoleaf

Gemfile

@@ -3,4 +3,4 @@
 source 'https://rubygems.org'
 
 gem 'color-converter'
-gem 'nokogiri'
+gem 'oga'

main.rb

@@ -1,13 +1,13 @@
 #! /usr/bin/env ruby
 # frozen_string_literal: true
 
-require 'nokogiri'
 require 'json'
 require 'uri'
 require 'net/http'
 require 'color_converter'
 require 'date'
 require 'open-uri'
+require 'oga'
 
 def colors
   case Date.today.strftime('%m%d')
@@ -25,7 +25,7 @@ def fetch_var(name)
 end
 
 def fetch_github_activity(length)
-  html = Nokogiri::HTML.parse(URI.open("https://github.com/#{fetch_var('GITHUB_USER')}"))
+  html = Oga.parse_html(URI.open("https://github.com/#{fetch_var('GITHUB_USER')}"))
   days = []
   boxes = html.css('rect.ContributionCalendar-day')
   boxes.each { |item| days << Integer(item['data-level']) unless item['data-date'].nil? }