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](https://github.com/sparklemotion/nokogiri/compare/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] <support@github.com>

Gemfile.lock

@@ -260,7 +260,7 @@ GEM
     net-smtp (0.3.3)
       net-protocol
     nio4r (2.5.9)
-    nokogiri (1.15.3)
+    nokogiri (1.15.4)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     nyan-cat-formatter (0.12.0)