Lazily load secrets whenever needed

lib/kamal/configuration/env/tag.rb

@@ -1,12 +1,13 @@
 class Kamal::Configuration::Env::Tag
-  attr_reader :name, :config
+  attr_reader :name, :config, :secrets
 
-  def initialize(name, config:)
+  def initialize(name, config:, secrets:)
     @name = name
     @config = config
+    @secrets = secrets
   end
 
   def env
-    Kamal::Configuration::Env.new(config: config)
+    Kamal::Configuration::Env.new(config: config, secrets: secrets)
   end
 end