Updated versions for Jekyll

docs/Gemfile

@@ -8,10 +8,11 @@ source "https://rubygems.org"
 #
 # This will help ensure the proper Jekyll version is running.
 # Happy Jekylling!
-gem "jekyll", "~> 3.7.0"
+#gem "jekyll", "~> 3.7.0"
+gem "github-pages", "~> 223", group: :jekyll_plugins
 
 # This is the default theme for new Jekyll sites. You may change this to anything you like.
-gem "hacker"
+# gem "hacker"
 
 # If you want to use GitHub Pages, remove the "gem "jekyll"" above and
 # uncomment the line below. To upgrade, run `bundle update github-pages`.
@@ -19,11 +20,11 @@ gem "hacker"
 
 # If you have any plugins, put them here!
 group :jekyll_plugins do
-  gem "jekyll-feed", "~> 0.6"
-  gem 'jekyll-seo-tag'
-  gem 'jekyll-theme-hacker'
-  gem 'jekyll-sitemap'
-  gem 'jemoji'
+  gem 'jekyll-seo-tag', '~> 2.7.1'
+  gem 'jekyll-theme-hacker', '~>0.2.0'
+  gem 'jekyll-sitemap', '~>1.4.0'
+  gem 'jemoji', '~>0.12.0'
+  gem 'jekyll-relative-links', '~>0.6.1'
 end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem