Add `last_used_at` field to personal_access_token API

doc/api/personal_access_tokens.md

@@ -40,8 +40,9 @@ curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/a
         "scopes": [
             "api"
         ],
-        "active": true,
         "user_id": 24,
+        "last_used_at": "2021-10-06T17:58:37.550Z",
+        "active": true,
         "expires_at": null
     }
 ]
@@ -61,8 +62,9 @@ curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/a
         "scopes": [
             "api"
         ],
-        "active": true,
         "user_id": 3,
+        "last_used_at": "2021-10-06T17:58:37.550Z",
+        "active": true,
         "expires_at": null
     }
 ]

lib/api/entities/personal_access_token.rb

@@ -3,7 +3,7 @@
 module API
   module Entities
     class PersonalAccessToken < Grape::Entity
-      expose :id, :name, :revoked, :created_at, :scopes, :user_id
+      expose :id, :name, :revoked, :created_at, :scopes, :user_id, :last_used_at
       expose :active?, as: :active
       expose :expires_at do |personal_access_token|
         personal_access_token.expires_at ? personal_access_token.expires_at.strftime("%Y-%m-%d") : nil

spec/lib/api/entities/personal_access_token_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe API::Entities::PersonalAccessToken do
+  describe '#as_json' do
+    let_it_be(:user) { create(:user) }
+    let_it_be(:token) { create(:personal_access_token, user: user, expires_at: nil) }
+
+    let(:entity) { described_class.new(token) }
+
+    it 'returns token data' do
+      expect(entity.as_json).to eq({
+         id: token.id,
+         name: token.name,
+         revoked: false,
+         created_at: token.created_at,
+         scopes: ['api'],
+         user_id: user.id,
+         last_used_at: nil,
+         active: true,
+         expires_at: nil
+       })
+    end
+  end
+end