Update fakefs requirement from ~> 0.6.0 to ~> 2.5.0

Updates the requirements on [fakefs](https://github.com/fakefs/fakefs) to permit the latest version.
- [Release notes](https://github.com/fakefs/fakefs/releases)
- [Changelog](https://github.com/fakefs/fakefs/blob/master/CHANGELOG.md)
- [Commits](fakefs/fakefs@v0.6.0...v2.5.0)

---
updated-dependencies:
- dependency-name: fakefs
  dependency-type: direct:development
...

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

rspec_api_documentation.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency "mustache", "~> 1.0", ">= 0.99.4"
 
   s.add_development_dependency "bundler", ">= 1.16"
-  s.add_development_dependency "fakefs", "~> 0.6.0"
+  s.add_development_dependency "fakefs", "~> 2.5.0"
   s.add_development_dependency "sinatra", "~> 2.0.8"
   s.add_development_dependency "aruba", "~> 0.14.14"
   s.add_development_dependency "capybara", "~> 3.39.2"