Bump nokogiri from 1.10.7 to 1.13.4

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.7 to 1.13.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/v1.13.4/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.10.7...v1.13.4)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -200,15 +200,16 @@ GEM
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.8.0)
     minima (2.5.1)
       jekyll (>= 3.5, < 5.0)
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
     minitest (5.14.0)
     multipart-post (2.1.1)
-    nokogiri (1.10.7)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.13.4)
+      mini_portile2 (~> 2.8.0)
+      racc (~> 1.4)
     octicons (9.3.1)
       nokogiri (>= 1.6.3.1)
     octokit (4.15.0)
@@ -217,6 +218,7 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (3.1.1)
+    racc (1.6.0)
     rb-fsevent (0.10.3)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
@@ -253,6 +255,7 @@ DEPENDENCIES
   faraday (< 1.0)
   github-pages
   jekyll-feed (~> 0.12)
+  jekyll-github-metadata
   jekyll-octicons
   minima (~> 2.5)
   tzinfo (~> 1.2)