Upgrade rspec-rails to 4.0.0.beta2

This solves a problem with Rails 6:
rspec/rspec-rails#2086

Author: thomasleese

Gemfile

@@ -49,7 +49,7 @@ group :development, :test do
   gem "jasmine", "3.5.0"
   gem "pry-byebug"
   gem "rails-controller-testing"
-  gem "rspec-rails", "3.8.2"
+  gem "rspec-rails", "4.0.0.beta2"
 end
 
 group :test do

Gemfile.lock

@@ -334,17 +334,17 @@ GEM
     rspec-its (1.3.0)
       rspec-core (>= 3.0.0)
       rspec-expectations (>= 3.0.0)
-    rspec-mocks (3.8.0)
+    rspec-mocks (3.8.1)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.8.0)
-    rspec-rails (3.8.2)
-      actionpack (>= 3.0)
-      activesupport (>= 3.0)
-      railties (>= 3.0)
-      rspec-core (~> 3.8.0)
-      rspec-expectations (~> 3.8.0)
-      rspec-mocks (~> 3.8.0)
-      rspec-support (~> 3.8.0)
+    rspec-rails (4.0.0.beta2)
+      actionpack (>= 4.2)
+      activesupport (>= 4.2)
+      railties (>= 4.2)
+      rspec-core (~> 3.8)
+      rspec-expectations (~> 3.8)
+      rspec-mocks (~> 3.8)
+      rspec-support (~> 3.8)
     rspec-support (3.8.2)
     rubocop (0.74.0)
       jaro_winkler (~> 1.5.1)
@@ -493,7 +493,7 @@ DEPENDENCIES
   redis (= 4.1.3)
   rspec-collection_matchers (~> 1.2.0)
   rspec-its (~> 1.3.0)
-  rspec-rails (= 3.8.2)
+  rspec-rails (= 4.0.0.beta2)
   sass-rails (= 6.0.0)
   select2-rails (= 4.0.3)
   shoulda (~> 3.5.0)