Address deprecation warning

Bellow is a code snippet:

```log
DEPRECATION WARNING: Defining enums with keyword arguments is deprecated and will be removed
in Rails 8.0.
```

Author: paranoicsan

app/models/lcms/engine/document_part.rb

@@ -5,7 +5,7 @@ module Engine
     class DocumentPart < ApplicationRecord
       belongs_to :renderer, polymorphic: true
 
-      enum context_type: { default: 0, gdoc: 1 }
+      enum :context_type, { default: 0, gdoc: 1 }
 
       default_scope { active }
 

app/models/lcms/engine/resource.rb

@@ -5,7 +5,7 @@ module Engine
     class Resource < ApplicationRecord
       include Filterable
 
-      enum resource_type: {
+      enum :resource_type, {
         resource: 1,
         podcast: 2,
         video: 3,

app/models/lcms/engine/staff_member.rb

@@ -5,7 +5,7 @@ module Engine
     class StaffMember < ApplicationRecord
       validates :first_name, :last_name, presence: true
       validates :bio, length: { maximum: 4096 }
-      enum staff_type: { staff: 1, board: 2 }
+      enum :staff_type, { staff: 1, board: 2 }
 
       scope :order_by_name, -> { order(:last_name) }
       scope :order_by_name_with_precedence, -> { order(:order, :last_name) }

app/models/lcms/engine/user.rb

@@ -10,7 +10,7 @@ class User < ApplicationRecord
       devise :database_authenticatable, :registerable, :confirmable,
              :recoverable, :rememberable, :trackable, :validatable
 
-      enum role: { admin: 1, user: 0 }
+      enum :role, { admin: 1, user: 0 }
 
       validates_presence_of :access_code, on: :create, unless: :admin?
       validates_presence_of :email, :role