Add missing image param (#3150)

spec/requests/admin/podcasts_spec.rb

@@ -2,6 +2,7 @@ require "rails_helper"
 
 RSpec.describe "Admin::Podcasts", type: :request do
   let(:super_admin) { create(:user, :super_admin) }
+  let(:image_file) { Rails.root.join("spec", "support", "fixtures", "images", "image1.jpeg") }
 
   before do
     sign_in super_admin
@@ -14,7 +15,8 @@ RSpec.describe "Admin::Podcasts", type: :request do
         description: "Super Podcast",
         feed_url: "http://feeds.feedburner.com/developertea",
         slug: "devtea",
-        main_color_hex: "333333"
+        main_color_hex: "333333",
+        image: Rack::Test::UploadedFile.new(image_file, "image/jpeg")
       }
     end