Bump nokogiri from 1.15.3 to 1.15.4

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.15.3 to 1.15.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.15.3...v1.15.4)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -132,11 +132,11 @@ GEM
     net-smtp (0.3.3)
       net-protocol
     nio4r (2.5.9)
-    nokogiri (1.15.3-aarch64-linux)
+    nokogiri (1.15.4-aarch64-linux)
       racc (~> 1.4)
-    nokogiri (1.15.3-arm64-darwin)
+    nokogiri (1.15.4-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.15.3-x86_64-linux)
+    nokogiri (1.15.4-x86_64-linux)
       racc (~> 1.4)
     octicons (19.5.0)
     octicons_helper (19.5.0)