Lock Sprockets to v3.x

Temporary fix for #3374

Author: spaghetticode

Gemfile

@@ -7,6 +7,11 @@ gemspec require: false
 rails_version = ENV['RAILS_VERSION'] || '~> 5.2.0'
 gem 'rails', rails_version, require: false
 
+# Temporarily locking sprockets to v3.x
+# see https://github.com/solidusio/solidus/issues/3374
+# and https://github.com/rails/sprockets-rails/issues/369
+gem 'sprockets', '~> 3'
+
 platforms :ruby do
   gem 'mysql2', '~> 0.5.0', require: false
   gem 'pg', '~> 1.0', require: false