Refactor micropub specific things out to a slice

slices/micropub/types.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require "dry/types"
+
+module Micropub
+  Types = Dry.Types
+
+  module Types
+    class Tag < Dry::Struct
+      attribute :label, Types::Coercible::String
+    end
+  end
+end