title: How to filter by nested attributes in JSONAPI?
body: <p>Assuming we have the following data structure</p>
  
  <pre><code>    "data": [
      {
          "type": "node--press",
          "id": "f04eab99-9174-4d00-bbbe-cdf45056660e",
          "attributes": {
              "nid": 130,
              "uuid": "f04eab99-9174-4d00-bbbe-cdf45056660e",
              "title": "TITLE OF NODE",
              "revision_translation_affected": true,
              "path": {
                  "alias": "/press/title-of-node",
                  "pid": 428,
                  "langcode": "es"
              }
  ...
  }
  </code></pre>
  
  <p>The data returned is compliant with JSON API standards, and I have no problem retrieving and processing it, except for the fact that I need to be able to filter the nodes returned by the path pid.</p>
  
  <p>How can I filter my data by path.pid?</p>
  
  <p>I have tried:
  - node-press?filter[path][pid]=428
  - node-press?filter[path][pid][value]=428</p>
  
  <p>to no avail</p>