title: After upgrade to rails 6.1.3, Active Storage return a 403 error
body: <p>After an upgrade to rails 6.1.3, Aws return a 403 error for <code>image_tag @item.photos.first</code>.
  All variants are displayed without any error.</p>
  <p><strong>item.rb</strong></p>
  <pre><code>class Item &lt; ApplicationRecord
    has_many_attached :photos, dependent: :destroy
  end
  </code></pre>
  <p><strong>items_controller</strong></p>
  <pre><code>  def show
      @item = Item.find[params[:id]
    end
  </code></pre>
  <p><strong>items/show.html.erb</strong></p>
  <pre><code>&lt;% if @item.photos.attached?%&gt;
              &lt;%= image_tag(@item.photos.first,
                srcset: [
                          [url_for(photos_variants(@item.photos.first, 300, 180)), &quot;375w&quot;],
                          [url_for(photos_variants(@item.photos.first, 500, 300)), &quot;512w&quot;],
                          [url_for(photos_variants(@item.photos.first, 750, 450)), &quot;768w&quot;],
                          [url_for(photos_variants(@item.photos.first, 1000, 600)), &quot;1024w&quot;],
                          [url_for(photos_variants(@item.photos.first, 1500, 900)), &quot;1980w&quot;]
                        ],
                sizes: &quot;100vw&quot;,
                alt: @item.name) %&gt;
   &lt;% end %&gt;
  
  </code></pre>