Update rubyzip requirement from > 1.1.1, < 2.4 to > 1.1.1, < 2.5

Updates the requirements on [rubyzip](https://github.com/rubyzip/rubyzip) to permit the latest version.
- [Release notes](https://github.com/rubyzip/rubyzip/releases)
- [Changelog](https://github.com/rubyzip/rubyzip/blob/master/Changelog.md)
- [Commits](rubyzip/rubyzip@v1.1.2...v2.4.1)

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

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

gepub.gemspec

@@ -17,7 +17,7 @@ Gem::Specification.new do |s|
   s.require_paths = ["lib"]
 
   s.add_runtime_dependency "nokogiri", ">= 1.8.2", "< 2.0"
-  s.add_runtime_dependency "rubyzip", "> 1.1.1", "< 2.4"
+  s.add_runtime_dependency "rubyzip", "> 1.1.1", "< 2.5"
   s.add_development_dependency "epubcheck-ruby"
   s.add_development_dependency "rake"
   s.add_development_dependency "rspec"