title: Query or deserialize json with dynamic keys using System.Text.Json
body: <p>I have json that looks like this, the key "123" could be any number.</p>
  
  <pre><code> {
     "key1": "",
     "key2": {
        "items": {
           "123": {
              "pageid": 123,
              "name": "data"
           }
        }
      }
   }
  </code></pre>
  
  <p>I want to deserialize or query the json with System.Text.Json so i can get the value of the key "name". How can I do that with System.Text.Json? I'm using .NET Core 3.1.</p>