Add and apply RSpec/BeEq rubocop rule

This rule was added in rubocop-rspec 2.9.0. Once again, we were applying
it about 50% of the time.

spec/models/verification/management/email_spec.rb

@@ -44,7 +44,7 @@ describe Verification::Management::Email do
                                                   document_number: "1234",
                                                   email: "inexisting@gmail.com")
 
-      expect(email.save).to eq(false)
+      expect(email.save).to be false
     end
 
     it "updates the user and sends an email" do