Bump nokogiri from 1.10.8 to 1.12.5

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.8 to 1.12.5.
- [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/v1.10.8...v1.12.5)

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

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

Gemfile.lock

@@ -64,14 +64,15 @@ GEM
     memoizable (0.4.2)
       thread_safe (~> 0.3, >= 0.3.1)
     method_source (0.9.0)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.6.1)
     multipart-post (2.0.0)
     nanoc (3.7.5)
       cri (~> 2.3)
     naught (1.1.0)
     nenv (0.3.0)
-    nokogiri (1.10.8)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.12.5)
+      mini_portile2 (~> 2.6.1)
+      racc (~> 1.4)
     notiffany (0.1.1)
       nenv (~> 0.1)
       shellany (~> 0.0)
@@ -80,6 +81,7 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.1)
+    racc (1.5.2)
     rack (2.2.3)
     rb-fsevent (0.10.2)
     rb-inotify (0.9.10)
@@ -132,7 +134,7 @@ DEPENDENCIES
   feedjira (~> 2.0.0)
   guard-nanoc (~> 1.0.3)
   nanoc (~> 3.7.5)
-  nokogiri (~> 1.10.8)
+  nokogiri (~> 1.12.5)
   rdiscount (~> 2.1.8)
   ri_cal (~> 0.8.8)
   rqrcode_png (~> 0.1.5)