Update index instructions, update gemfile

Gemfile

@@ -5,16 +5,15 @@ source 'https://rubygems.org'
 git_source(:github) { |repo_name| "https://github.com/#{repo_name}" }
 
 # Synchronize with https://pages.github.com/versions
-ruby '>=2.7.1'
+ruby '>=3.2.3'
 
 gem 'faraday', '0.17.3'
 
 group :jekyll_plugins do
-  gem 'github-pages', '206'
-  gem 'jekyll-get-json', "~> 1.0.0"
-  gem 'jekyll', '3.8.7'
-end
-
-if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.0.0')
-    gem 'webrick', '>= 1.6.1'
+    gem 'github-pages', '232'
+    gem 'jekyll-redirect-from'
+    gem 'jekyll-get-json', "~> 1.0.0"
+    gem 'jekyll', '3.10.0'
+    gem 'jekyll-feed', '0.17.0'
+    gem 'webrick', '~> 1.8'
 end

index.md

@@ -11,15 +11,17 @@ permalink: index.html  # Is the only page that doesn't follow the pattern /:path
 > Our new lesson infrastructure, [The Carpentries Workbench](https://carpentries.github.io/workbench/)
 > became the default for official Carpentries lessons in May 2023.
 >
-> This new infrastructure is designed to be more accessible and easier to use than the styles
-> infrastructure by separating tools from the content.
+> The Workbench is designed to be more accessible and easier to use than the styles
+> infrastructure by separating tools from the content. As such, using this repository for
+> lessons is no longer supported by The Carpentries Core Team.
 >
-> **If you would like to create a new lesson, we encourage you to use The Workbench.**
+> **If you would like to create a new lesson, we encourage you to use The Workbench templates below.**
+>
+> - Markdown Lesson Template: <https://github.com/carpentries/workbench-template-md>
+> - R Markdown Lesson Template: <https://github.com/carpentries/workbench-template-rmd>
 >
 > ### Resources
 > 
-> - Markdown Lesson Template Generator: <https://bit.ly/new-lesson-md/>
-> - R Markdown Lesson Template Generator: <https://bit.ly/new-lesson-rmd/>
 > - Lesson Maintainer/Author Documentation: <https://carpentries.github.io/sandpaper-docs/>
 > - Migrating between Carpentries lesson infrastructures:
 >     - A semi-automated workflow for migrating from the previous infrastructure to the Workbench: <https://carpentries.github.io/sandpaper-docs/migrating-from-styles.html>
@@ -34,7 +36,7 @@ permalink: index.html  # Is the only page that doesn't follow the pattern /:path
 For guidelines on how to develop curriculum content, please visit
 [The Carpentries Curriculum Development Handbook][curriculum-handbook].
 
-This lesson shows how to use [The Carpentries]({{ site.carpentries_site}})
+This lesson shows how to use [The Carpentries]({{ site.carpentries_site }})
 lesson template. The materials below assume familiarity with tools such as GitHub, Markdown,
 and Jekyll. For more guidance, please visit the [Technological introductions][tech-intro]
 section of The Carpentries Curriculum Development Handbook.