Update html-pipeline requirement from ~> 2.14 to >= 2.14, < 4.0

Updates the requirements on [html-pipeline](https://github.com/gjtorikian/html-pipeline) to permit the latest version.
- [Release notes](https://github.com/gjtorikian/html-pipeline/releases)
- [Changelog](https://github.com/gjtorikian/html-pipeline/blob/main/CHANGELOG.md)
- [Commits](gjtorikian/html-pipeline@v2.14.0...v2.14.3)

---
updated-dependencies:
- dependency-name: html-pipeline
  dependency-type: direct:production
...

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Author: dependabot[bot]

publify_core.gemspec

@@ -30,7 +30,7 @@ Gem::Specification.new do |s|
   s.add_dependency "devise_zxcvbn", "~> 6.0"
   s.add_dependency "fog-aws", "~> 3.2"
   s.add_dependency "fog-core", "~> 2.2"
-  s.add_dependency "html-pipeline", "~> 2.14"
+  s.add_dependency "html-pipeline", ">= 2.14", "< 4.0"
   s.add_dependency "html-pipeline-hashtag", "~> 0.1.2"
   s.add_dependency "jquery-rails", ">= 4.5", "< 4.7"
   s.add_dependency "jquery-ui-rails", ">= 7", "< 9"