Refactor forwardable require calls

lib/producer/core.rb

@@ -1,3 +1,5 @@
+require 'forwardable'
+
 # task actions
 require 'producer/core/action'
 require 'producer/core/actions/echo'

lib/producer/core/action.rb

@@ -1,8 +1,6 @@
 module Producer
   module Core
     class Action
-      require 'forwardable'
-
       extend Forwardable
       def_delegators :@env, :input, :output, :remote
       def_delegators :remote, :fs

lib/producer/core/remote/environment.rb

@@ -12,8 +12,6 @@ module Producer
           end
         end
 
-        require 'forwardable'
-
         extend Forwardable
         def_delegators :@variables, :[], :key?
 

lib/producer/core/test.rb

@@ -1,8 +1,6 @@
 module Producer
   module Core
     class Test
-      require 'forwardable'
-
       extend Forwardable
       def_delegators :@env, :remote
       def_delegators :remote, :fs