title: Laravel Voyager - two dropdown "Category" and "Subcategory"
body: <p>I am using Laravel Voyager admin panel.</p>
  
  <p>I have a 'products' table where PRODUCT has parent SUBCATEGORY and CATEGORY. I have also made these relationships: 'product-subcategory' and 'product-category'.</p>
  
  <p><img src="https://i.stack.imgur.com/hf8o5.png" alt="Screenshot"></p>
  
  <p>So, when I want to add new product, I can choose CATEGORY and SUBCATEGORY from dropdown.</p>
  
  <p>The problem is, SUBCATEGORY dropdown shows all of the subcategories:</p>
  
  <p>I want see the SUBCATEGORIES only from the CATEGORY I choose. (like we get the column names of specified MODEL(for referencing) when we create relationships in voyager)</p>
  
  <p>The reason I want this is to prevent adding products under the wrong Category and Subcategory.</p>
  
  <p>Is there a way to achieve this? Should I use some JSON in the 'Optional Details' field?</p>