Bump nokogiri from 1.10.9 to 1.13.4

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.9 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@v1.10.9...v1.13.4)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -63,12 +63,13 @@ GEM
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2020.0512)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.8.0)
     minitest (5.14.1)
     multi_xml (0.6.0)
     nenv (0.3.0)
-    nokogiri (1.10.9)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.13.4)
+      mini_portile2 (~> 2.8.0)
+      racc (~> 1.4)
     nori (2.6.0)
     notiffany (0.1.3)
       nenv (~> 0.1)
@@ -79,6 +80,7 @@ GEM
     pry-nav (0.3.0)
       pry (>= 0.9.10, < 0.13.0)
     public_suffix (4.0.5)
+    racc (1.6.0)
     rack (2.2.3)
     rainbow (3.0.0)
     rake (13.0.1)