Update rspec to 3.8.0; remove rspec-its

Gemfile

@@ -2,8 +2,7 @@ source "http://rubygems.org"
 
 group :development, :test do
   gem 'listen', '~> 0.5.0'
-  gem 'rspec', '~> 2.0'
-  gem 'rspec-its', '~> 1.0.0'
+  gem 'rspec', '~> 3.8.0'
   gem 'rubocop', '0.49.1', require: false
   gem 'simplecov', '~> 0.9.0', require: false
   gem 'vcr', '~> 4.0.0'

Gemfile.lock

@@ -18,17 +18,19 @@ GEM
     rainbow (2.2.2)
       rake
     rake (12.3.1)
-    rspec (2.99.0)
-      rspec-core (~> 2.99.0)
-      rspec-expectations (~> 2.99.0)
-      rspec-mocks (~> 2.99.0)
-    rspec-core (2.99.2)
-    rspec-expectations (2.99.2)
-      diff-lcs (>= 1.1.3, < 2.0)
-    rspec-its (1.0.1)
-      rspec-core (>= 2.99.0.beta1)
-      rspec-expectations (>= 2.99.0.beta1)
-    rspec-mocks (2.99.4)
+    rspec (3.8.0)
+      rspec-core (~> 3.8.0)
+      rspec-expectations (~> 3.8.0)
+      rspec-mocks (~> 3.8.0)
+    rspec-core (3.8.0)
+      rspec-support (~> 3.8.0)
+    rspec-expectations (3.8.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.8.0)
+    rspec-mocks (3.8.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.8.0)
+    rspec-support (3.8.0)
     rubocop (0.49.1)
       parallel (~> 1.10)
       parser (>= 2.3.3.1, < 3.0)
@@ -54,8 +56,7 @@ PLATFORMS
 
 DEPENDENCIES
   listen (~> 0.5.0)
-  rspec (~> 2.0)
-  rspec-its (~> 1.0.0)
+  rspec (~> 3.8.0)
   rubocop (= 0.49.1)
   simplecov (~> 0.9.0)
   vcr (~> 4.0.0)

spec/spec_helper.rb

 ROOT_PATH = File.expand_path(File.join(File.dirname(__FILE__), ".."))
 
-require 'rspec/its'
-
 require 'simplecov'
 SimpleCov.start