Bump github-pages and jekyll in /docs (#728)

Bumps [github-pages](https://github.com/github/pages-gem) and [jekyll](https://github.com/jekyll/jekyll). These dependencies needed to be updated together.

Updates `github-pages` from 225 to 228
- [Release notes](https://github.com/github/pages-gem/releases)
- [Commits](github/pages-gem@v225...v228)

Updates `jekyll` from 3.9.0 to 3.9.3
- [Release notes](https://github.com/jekyll/jekyll/releases)
- [Changelog](https://github.com/jekyll/jekyll/blob/master/History.markdown)
- [Commits](jekyll/jekyll@v3.9.0...v3.9.3)

---
updated-dependencies:
- dependency-name: github-pages
  dependency-type: direct:development
  update-type: version-update:semver-major
- dependency-name: jekyll
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/Gemfile

@@ -7,12 +7,12 @@ source "https://rubygems.org"
 #
 # This will help ensure the proper Jekyll version is running.
 # Happy Jekylling!
-gem "jekyll", "~> 3.9.0"
+gem "jekyll", "~> 3.9.3"
 # This is the default theme for new Jekyll sites. You may change this to anything you like.
 gem "minima", "~> 2.5"
 # If you want to use GitHub Pages, remove the "gem "jekyll"" above and
 # uncomment the line below. To upgrade, run `bundle update github-pages`.
-gem "github-pages", "~> 225", group: :jekyll_plugins
+gem "github-pages", "~> 228", group: :jekyll_plugins
 # If you have any plugins, put them here!
 group :jekyll_plugins do
 end

docs/Gemfile.lock

@@ -34,12 +34,12 @@ GEM
     ffi (1.16.3)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
-    github-pages (225)
+    github-pages (228)
       github-pages-health-check (= 1.17.9)
-      jekyll (= 3.9.0)
+      jekyll (= 3.9.3)
       jekyll-avatar (= 0.7.0)
       jekyll-coffeescript (= 1.1.1)
-      jekyll-commonmark-ghpages (= 0.2.0)
+      jekyll-commonmark-ghpages (= 0.4.0)
       jekyll-default-layout (= 0.1.4)
       jekyll-feed (= 0.15.1)
       jekyll-gist (= 1.5.0)
@@ -71,12 +71,12 @@ GEM
       jekyll-theme-time-machine (= 0.2.0)
       jekyll-titles-from-headings (= 0.5.3)
       jemoji (= 0.12.0)
-      kramdown (= 2.3.1)
+      kramdown (= 2.3.2)
       kramdown-parser-gfm (= 1.1.0)
-      liquid (= 4.0.3)
+      liquid (= 4.0.4)
       mercenary (~> 0.3)
       minima (= 2.5.1)
-      nokogiri (>= 1.12.5, < 2.0)
+      nokogiri (>= 1.13.6, < 2.0)
       rouge (= 3.26.0)
       terminal-table (~> 1.4)
     github-pages-health-check (1.17.9)
@@ -89,13 +89,13 @@ GEM
       activesupport (>= 2)
       nokogiri (>= 1.4)
     http_parser.rb (0.8.0)
-    i18n (0.9.5)
+    i18n (1.14.1)
       concurrent-ruby (~> 1.0)
-    jekyll (3.9.0)
+    jekyll (3.9.3)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
-      i18n (~> 0.7)
+      i18n (>= 0.7, < 2)
       jekyll-sass-converter (~> 1.0)
       jekyll-watch (~> 2.0)
       kramdown (>= 1.17, < 3)
@@ -111,11 +111,11 @@ GEM
       coffee-script-source (~> 1.11.1)
     jekyll-commonmark (1.4.0)
       commonmarker (~> 0.22)
-    jekyll-commonmark-ghpages (0.2.0)
-      commonmarker (~> 0.23.4)
+    jekyll-commonmark-ghpages (0.4.0)
+      commonmarker (~> 0.23.7)
       jekyll (~> 3.9.0)
       jekyll-commonmark (~> 1.4.0)
-      rouge (>= 2.0, < 4.0)
+      rouge (>= 2.0, < 5.0)
     jekyll-default-layout (0.1.4)
       jekyll (~> 3.0)
     jekyll-feed (0.15.1)
@@ -199,11 +199,11 @@ GEM
       gemoji (~> 3.0)
       html-pipeline (~> 2.2)
       jekyll (>= 3.0, < 5.0)
-    kramdown (2.3.1)
+    kramdown (2.3.2)
       rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
-    liquid (4.0.3)
+    liquid (4.0.4)
     listen (3.8.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -261,8 +261,8 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
-  github-pages (~> 225)
-  jekyll (~> 3.9.0)
+  github-pages (~> 228)
+  jekyll (~> 3.9.3)
   minima (~> 2.5)
   tzinfo (~> 1.2)
   tzinfo-data