Bump mocha from 1.3.0 to 1.4.0

Bumps [mocha](https://github.com/freerange/mocha) from 1.3.0 to 1.4.0.
- [Release notes](https://github.com/freerange/mocha/releases)
- [Changelog](https://github.com/freerange/mocha/blob/master/RELEASE.md)
- [Commits](freerange/mocha@v1.3.0...v1.4.0)

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

Gemfile

@@ -38,7 +38,7 @@ group :test do
   gem 'capybara', '2.18.0'
   gem 'ci_reporter_minitest', '1.0.0'
   gem 'govuk-content-schema-test-helpers', '~> 1.6.1'
-  gem 'mocha', '1.3.0', require: false
+  gem 'mocha', '1.4.0', require: false
   gem 'rails-controller-testing'
   gem 'shoulda', '3.5.0'
   gem 'simplecov', '0.16.1'

Gemfile.lock

@@ -149,7 +149,7 @@ GEM
     mini_mime (1.0.0)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
-    mocha (1.3.0)
+    mocha (1.4.0)
       metaclass (~> 0.0.1)
     money (6.10.1)
       i18n (>= 0.6.4, < 1.0)
@@ -318,7 +318,7 @@ DEPENDENCIES
   govuk_navigation_helpers (~> 7.3.0)
   govuk_publishing_components (~> 5.5.4)
   json (~> 2.1.0)
-  mocha (= 1.3.0)
+  mocha (= 1.4.0)
   plek (= 2.1.1)
   pry-byebug
   rack_strip_client_ip (= 0.0.2)