Depracation warning for Rails 7.2 fixed - enum (#1386)

* Update navigation_item.rb

Depracation warning for Rails 7.2.11/8 fixed.
in Rails 8.0. Positional arguments should be used instead:

* Update navigation_item.rb

support for older Rails version added

app/models/spina/navigation_item.rb

@@ -6,7 +6,11 @@ class NavigationItem < ApplicationRecord
     # NavigationItems can be of two different kinds:
     # - A link to a page
     # - A link to a URL
-    enum kind: {page: "page", url: "url"}, _suffix: true
+    if Rails.version >= '7.2'
+      enum :kind, {page: "page", url: "url"}, suffix: true
+    else
+      enum kind: {page: "page", url: "url"}, _suffix: true
+    end
 
     has_ancestry