Add RuboCop RSpec support

Previously, RuboCop RSpec failed to detect RSpec aliases. A number of
cops were failing false offences, and some cops were unable to lint, as
they were skipping locally defined RSpec aliases taking them for
arbitrary blocks and method calls.

See:
 - rubocop/rubocop-rspec#1077
 - rubocop/rubocop-rspec#956
 - palkan#103

Author: pirj

.rubocop-rspec-aliases.yml

@@ -0,0 +1,17 @@
+RSpec:
+  Language:
+    ExampleGroups:
+      Regular:
+        - describe_rule
+      Focused:
+        - fdescribe_rule
+      Skipped:
+        - xdescribe_rule
+    Includes:
+      Examples:
+        - succeed
+        - failed
+        - fsucceed
+        - ffailed
+        - xsucceed
+        - xfailed

action_policy.gemspec

@@ -13,7 +13,7 @@ Gem::Specification.new do |spec|
   spec.homepage = "https://github.com/palkan/action_policy"
   spec.license = "MIT"
 
-  spec.files = Dir.glob("lib/**/*") + Dir.glob("lib/.rbnext/**/*") + %w[README.md LICENSE.txt CHANGELOG.md]
+  spec.files = Dir.glob("lib/**/*") + Dir.glob("lib/.rbnext/**/*") + %w[README.md LICENSE.txt CHANGELOG.md] + %w[rubocop-rspec-aliases.yml]
 
   spec.metadata = {
     "bug_tracker_uri" => "http://github.com/palkan/action_policy/issues",

docs/testing.md

@@ -388,3 +388,13 @@ describe "users/index.html.slim" do
   end
 end
 ```
+
+## Linting with RuboCop RSpec
+
+When you lint your RSpec spec files with `rubocop-rspec`, it will fail to detect RSpec aliases that Action Policy defines.
+Make sure to use `rubocop-rspec` 2.0 or newer and add the following to your `.rubocop.yml`:
+
+```yaml
+inherit_gem:
+  action_policy: .rubocop-rspec-aliases.yml
+```