Remove unused axe-capybara dependency

The contents of the [axe-capybara.rb][] file aren't necessary for
`capybara_accessibility_audit`'s pattern of usage.

This also sheds an indirect and unstated `selenium-webdrivers`
dependency.

[axe-capybara.rb]: https://github.com/dequelabs/axe-core-gems/blob/develop/packages/axe-core-capybara/lib/axe-capybara.rb

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- Remove unused `require "axe-capybara"` statement
+
+  *Sean Doyle*
+
 - Drop support for [End of Life version 2.7](https://www.ruby-lang.org/en/downloads/branches/)
 
   *Sean Doyle*

capybara_accessibility_audit.gemspec

@@ -21,6 +21,6 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "rails", ">= 6.1"
   spec.add_dependency "capybara"
-  spec.add_dependency "axe-core-capybara"
+  spec.add_dependency "axe-core-api"
   spec.add_dependency "zeitwerk"
 end

lib/capybara_accessibility_audit/audit_system_test_extensions.rb

@@ -1,4 +1,3 @@
-require "axe-capybara"
 require "axe/matchers/be_axe_clean"
 
 module CapybaraAccessibilityAudit