Upgrade dependencies to the latest versions

website/.gitignore

@@ -1,6 +1,5 @@
 # Generated by Bundler and Jekyll.
 .bundle/
-Gemfile.lock
 .jekyll-cache/
 .jekyll-metadata
 .sass-cache/

website/Gemfile

@@ -1,9 +1,17 @@
 ruby File.read(".ruby-version").strip
 
 source "https://rubygems.org"
-gem "diffy", "~> 3.4.0"
-gem "github-pages", "~> 227"
-gem "json", "~> 2.6"
-gem "mustache", "~> 1.0"
-gem "rake", "~> 13.0" # Required for "just-the-docs" theme
-gem "webrick", "~> 1.7"
+
+group :site_content_generation_dependencies do
+  gem "diffy", "~> 3.4.0"
+  gem "json", "~> 2.6"
+  gem "mustache", "~> 1.0"
+end
+
+group :jekyll_site_dependencies do
+  gem "jekyll", "~> 4.2"
+  gem "jekyll-remote-theme", "~>0.4"
+  gem "jekyll-seo-tag", "~>2.8"
+  gem "rake", "~> 13.0" # Required for "just-the-docs" theme
+  gem "webrick", "~> 1.7"
+end

website/Gemfile.lock

@@ -0,0 +1,90 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.8.1)
+      public_suffix (>= 2.0.2, < 6.0)
+    colorator (1.1.0)
+    concurrent-ruby (1.1.10)
+    diffy (3.4.2)
+    em-websocket (0.5.3)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0)
+    eventmachine (1.2.7)
+    ffi (1.15.5)
+    forwardable-extended (2.6.0)
+    http_parser.rb (0.8.0)
+    i18n (1.12.0)
+      concurrent-ruby (~> 1.0)
+    jekyll (4.2.2)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      em-websocket (~> 0.5)
+      i18n (~> 1.0)
+      jekyll-sass-converter (~> 2.0)
+      jekyll-watch (~> 2.0)
+      kramdown (~> 2.3)
+      kramdown-parser-gfm (~> 1.0)
+      liquid (~> 4.0)
+      mercenary (~> 0.4.0)
+      pathutil (~> 0.9)
+      rouge (~> 3.0)
+      safe_yaml (~> 1.0)
+      terminal-table (~> 2.0)
+    jekyll-remote-theme (0.4.3)
+      addressable (~> 2.0)
+      jekyll (>= 3.5, < 5.0)
+      jekyll-sass-converter (>= 1.0, <= 3.0.0, != 2.0.0)
+      rubyzip (>= 1.3.0, < 3.0)
+    jekyll-sass-converter (2.2.0)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-seo-tag (2.8.0)
+      jekyll (>= 3.8, < 5.0)
+    jekyll-watch (2.2.1)
+      listen (~> 3.0)
+    json (2.6.2)
+    kramdown (2.4.0)
+      rexml
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
+    liquid (4.0.3)
+    listen (3.7.1)
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
+    mercenary (0.4.0)
+    mustache (1.1.1)
+    pathutil (0.16.2)
+      forwardable-extended (~> 2.6)
+    public_suffix (5.0.0)
+    rake (13.0.6)
+    rb-fsevent (0.11.2)
+    rb-inotify (0.10.1)
+      ffi (~> 1.0)
+    rexml (3.2.5)
+    rouge (3.30.0)
+    rubyzip (2.3.2)
+    safe_yaml (1.0.5)
+    sassc (2.4.0)
+      ffi (~> 1.9)
+    terminal-table (2.0.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
+    unicode-display_width (1.8.0)
+    webrick (1.7.0)
+
+PLATFORMS
+  x86_64-linux
+
+DEPENDENCIES
+  diffy (~> 3.4.0)
+  jekyll (~> 4.2)
+  jekyll-remote-theme (~> 0.4)
+  jekyll-seo-tag (~> 2.8)
+  json (~> 2.6)
+  mustache (~> 1.0)
+  rake (~> 13.0)
+  webrick (~> 1.7)
+
+RUBY VERSION
+   ruby 3.1.2p20
+
+BUNDLED WITH
+   2.3.7

website/_config.yml

@@ -6,7 +6,7 @@ description: >-
   Error Prone extensions: extra bug checkers and a large battery of Refaster
   rules.
 
-remote_theme: just-the-docs/just-the-docs
+remote_theme: just-the-docs/just-the-docs@v0.4.0.rc3
 plugins:
   - jekyll-remote-theme