Bump nokogiri from 1.12.5 to 1.13.6

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.12.5 to 1.13.6.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](https://github.com/sparklemotion/nokogiri/compare/v1.12.5...v1.13.6)

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

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

Gemfile

@@ -7,7 +7,7 @@ gem 'middleman', '~> 4.3.4'
 gem 'middleman-autoprefixer', '~> 2.10.0'
 gem 'middleman-sprockets', '~> 4.1.1'
 gem 'middleman-syntax', '~> 3.2.0'
-gem 'nokogiri', '~> 1.12.5'
+gem 'nokogiri', '~> 1.13.6'
 gem 'rack', '~> 2.2.3'
 gem 'redcarpet', '~> 3.5.1'
 gem 'rouge', '~> 3.26.0'

Gemfile.lock

@@ -77,10 +77,10 @@ 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 (1.13.6)
+      mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     padrino-helpers (0.13.3.4)
       i18n (~> 0.6, >= 0.6.7)
@@ -90,7 +90,7 @@ GEM
       activesupport (>= 3.1)
     parallel (1.20.1)
     public_suffix (4.0.6)
-    racc (1.5.2)
+    racc (1.6.0)
     rack (2.2.3)
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
@@ -122,7 +122,7 @@ DEPENDENCIES
   middleman-autoprefixer (~> 2.10.0)
   middleman-sprockets (~> 4.1.1)
   middleman-syntax (~> 3.2.0)
-  nokogiri (~> 1.12.5)
+  nokogiri (~> 1.13.6)
   rack (~> 2.2.3)
   redcarpet (~> 3.5.1)
   rouge (~> 3.26.0)