Remove jasmine ruby gem and its requiring

This was missed from the pull request that
replaced the jasmine ruby gem with the
jasmine-browser-runner:

#382

Rakefile

@@ -1,6 +1,5 @@
 require "bundler/gem_tasks"
 require "rspec/core/rake_task"
-require "jasmine"
 
 RSpec::Core::RakeTask.new(:spec)
 

govuk_tech_docs.gemspec

@@ -25,6 +25,7 @@ Gem::Specification.new do |spec|
   files_in_git = `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
 
   # Include assets from GOV.UK Frontend library in the distributed gem
+  # Extra line
   govuk_frontend_assets = Dir["node_modules/govuk-frontend/**/*.{scss,js,mjs,woff,woff2,png,svg,ico}", "node_modules/govuk-frontend/dist/govuk/assets/manifest.json"]
 
   spec.files         = files_in_git + govuk_frontend_assets
@@ -57,7 +58,6 @@ Gem::Specification.new do |spec|
 
   spec.add_development_dependency "byebug"
   spec.add_development_dependency "capybara", "~> 3.32"
-  spec.add_development_dependency "jasmine", "~> 3.5"
   spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rspec", "~> 3.9"
   spec.add_development_dependency "rubocop-govuk", "~> 4.10"