Bump nokogiri from 1.12.5 to 1.13.9

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.12.5 to 1.13.9.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.12.5...v1.13.9)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile

@@ -8,6 +8,6 @@ gem 'middleman-autoprefixer', '~> 3.0'
 gem 'middleman-sprockets', '~> 4.1'
 gem 'rouge', '~> 3.21'
 gem 'redcarpet', '~> 3.5.0'
-gem 'nokogiri', '~> 1.12.1'
+gem 'nokogiri', '~> 1.13.9'
 gem 'sass'
 gem 'webrick'

Gemfile.lock

@@ -80,10 +80,10 @@ GEM
     middleman-syntax (3.2.0)
       middleman-core (>= 3.2)
       rouge (~> 3.2)
-    mini_portile2 (2.6.1)
+    mini_portile2 (2.8.0)
     minitest (5.14.4)
-    nokogiri (1.12.5)
-      mini_portile2 (~> 2.6.1)
+    nokogiri (1.13.9)
+      mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     padrino-helpers (0.15.1)
       i18n (>= 0.6.7, < 2)
@@ -93,7 +93,7 @@ GEM
     parallel (1.21.0)
     parslet (2.0.0)
     public_suffix (4.0.6)
-    racc (1.5.2)
+    racc (1.6.0)
     rack (2.2.3)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
@@ -132,7 +132,7 @@ DEPENDENCIES
   middleman-autoprefixer (~> 3.0)
   middleman-sprockets (~> 4.1)
   middleman-syntax (~> 3.2)
-  nokogiri (~> 1.12.1)
+  nokogiri (~> 1.13.9)
   redcarpet (~> 3.5.0)
   rouge (~> 3.21)
   sass