Require Dalli 3 in our test suite

The code itself still works with Dailli 2, but we are now only testing
against Dalli 3.

Author: rafaelfranca

Gemfile

@@ -50,7 +50,7 @@ group :doc do
 end
 
 # Active Support
-gem "dalli"
+gem "dalli", ">= 3.0.1"
 gem "listen", "~> 3.3", require: false
 gem "libxml-ruby", platforms: :ruby
 gem "connection_pool", require: false

Gemfile.lock

@@ -543,7 +543,7 @@ DEPENDENCIES
   capybara (>= 3.26)
   connection_pool
   cssbundling-rails
-  dalli
+  dalli (>= 3.0.1)
   debug (>= 1.1.0)
   delayed_job
   delayed_job_active_record