update marlinfw.org ruby and jekyll

[ellensp]

Update marlinfw.org to comply with Github pages dependency versions https://pages.github.com/versions/

I've tested this on local linux machine, it looks complete, but needs checking by someone familiar with every facet.. I haven't tested .github/workflows/jekyll-pub.yml

There are new docs coming from thisiskeithb on how to install locally for all the OS's

My notes: Install Ruby 3.3.4 on Ubuntu

I Installed https://github.com/rbenv/rbenv as the os version is not recent, mostly following https://shape.host/resources/step-by-step-guide-installing-ruby-on-rails-with-rbenv-on-ubuntu-22-04

Enter these commands

  sudo apt update
  sudo apt install git curl libssl-dev libreadline-dev zlib1g-dev autoconf bison build-essential libyaml-dev libreadline-dev libncurses5-dev libffi-dev libgdbm-dev
  curl -fsSL https://github.com/rbenv/rbenv-installer/raw/HEAD/bin/rbenv-installer | bash

  echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
  echo 'eval "$(rbenv init -)"' >> ~/.bashrc

  source ~/.bashrc

  rbenv install 3.3.4
  rbenv global 3.3.4
  ruby -v

  echo '# Install Ruby Gems to ~/gems' >> ~/.bashrc
  echo 'export GEM_HOME="$HOME/gems"' >> ~/.bashrc
  echo 'export PATH="$HOME/gems/bin:$PATH"' >> ~/.bashrc
  source ~/.bashrc

  gem install bundler

Get MarlinDocumentation with updated files from this PR

change into MarlinDocumentation directory and enter these commands

  bundle config set path 'vendor/bundle'
  bundle install
  bundle exec jekyll -v
  bundle exec jekyll serve --watch --incremental

[thisiskeithb]

I've confirmed that everything builds in clean installs of Ubuntu 24.04 LTS, Windows 10, and macOS Monterey 12.7.6 (limited by my hardware).

I've updated my "Overhaul README" PR, so it's now tied to these updates:

• https://github.com/MarlinFirmware/MarlinDocumentation/pull/575

[thisiskeithb]

One minor suggestion: Add a .ruby-version file in the project root with 3.3.4 in it so the Ruby version is switched automatically for those that have configured their system to do so.

[ellensp]

I was thinking more add it to .gitignore, then users can play with other version in the future without fighting