fix: Security upgrade github-pages from 214 to 215 (#1679)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-ADDRESSABLE-1316242

docs/Gemfile

@@ -1,3 +1,3 @@
 source 'https://rubygems.org'
-gem 'github-pages', '>= 214', group: :jekyll_plugins
+gem 'github-pages', '>= 215', group: :jekyll_plugins
 gem "nokogiri", ">= 1.11.4"

docs/Gemfile.lock

@@ -1,13 +1,13 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (6.0.3.7)
+    activesupport (6.0.4)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
       zeitwerk (~> 2.2, >= 2.2.2)
-    addressable (2.7.0)
+    addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
     coffee-script (2.4.1)
       coffee-script-source
@@ -16,8 +16,8 @@ GEM
     colorator (1.1.0)
     commonmarker (0.17.13)
       ruby-enum (~> 0.5)
-    concurrent-ruby (1.1.8)
-    dnsruby (1.61.5)
+    concurrent-ruby (1.1.9)
+    dnsruby (1.61.7)
       simpleidn (~> 0.1)
     em-websocket (0.5.2)
       eventmachine (>= 0.12.9)
@@ -27,21 +27,25 @@ GEM
     eventmachine (1.2.7)
     eventmachine (1.2.7-x64-mingw32)
     execjs (2.8.1)
-    faraday (1.4.2)
+    faraday (1.5.0)
       faraday-em_http (~> 1.0)
       faraday-em_synchrony (~> 1.0)
       faraday-excon (~> 1.1)
+      faraday-httpclient (~> 1.0.1)
       faraday-net_http (~> 1.0)
       faraday-net_http_persistent (~> 1.1)
+      faraday-patron (~> 1.0)
       multipart-post (>= 1.2, < 3)
       ruby2_keywords (>= 0.0.4)
     faraday-em_http (1.0.0)
     faraday-em_synchrony (1.0.0)
     faraday-excon (1.1.0)
+    faraday-httpclient (1.0.1)
     faraday-net_http (1.0.1)
     faraday-net_http_persistent (1.1.0)
-    ffi (1.15.1)
-    ffi (1.15.1-x64-mingw32)
+    faraday-patron (1.0.0)
+    ffi (1.15.3)
+    ffi (1.15.3-x64-mingw32)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
     github-pages (215)
@@ -242,7 +246,7 @@ GEM
     ruby-enum (0.9.0)
       i18n
     ruby2_keywords (0.0.4)
-    rubyzip (2.3.0)
+    rubyzip (2.3.2)
     safe_yaml (1.0.5)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
@@ -273,8 +277,8 @@ PLATFORMS
   x64-mingw32
 
 DEPENDENCIES
-  github-pages (>= 214)
+  github-pages (>= 215)
   nokogiri (>= 1.11.4)
 
 BUNDLED WITH
-   2.2.17
+   2.1.4