title: Why apollo client:codegen is not generate types?
body: <p>im trying to get the types defined in my Apollo server</p>
  
  <p>by first, downloading the schema effectively:</p>
  
  <pre><code>apollo client:download-schema src/code/queries/schemas/schema.json --endpoint http://localhost:4000/
  </code></pre>
  
  <p>that command generates the following .json, reduced it for demonstration purposes.</p>
  
  <pre><code>{
  "__schema": {
  "queryType": {
    "name": "Query"
  },
  "mutationType": {
    "name": "Mutation"
  },
  "subscriptionType": null,
  "types": [
    {
      "kind": "OBJECT",
      "name": "Query",
      "description": null,
      "fields": [
        {
          "name": "UserInformation",
          "description": null,
          "args": [],
          "type": {
            "kind": "OBJECT",
            "name": "User",
            "ofType": null
          },
          "isDeprecated": false,
          "deprecationReason": null
        }
      ],
      "inputFields": null,
      "interfaces": [],
      "enumValues": null,
      "possibleTypes": null
    },
    {
      "kind": "OBJECT",
      "name": "User",
      "description": null,
      "fields": [
        {
          "name": "firstName",
          "description": null,
          "args": [],
          "type": {
            "kind": "SCALAR",
            "name": "String",
            "ofType": null
          },
          "isDeprecated": false,
          "deprecationReason": null
        },
        {
          "name": "secondName",
          "description": null,
          "args": [],
          "type": {
            "kind": "SCALAR",
            "name": "String",
            "ofType": null..........
  </code></pre>
  
  <p>then tying to generate the types as typescript without success:</p>
  
  <pre><code>   apollo client:codegen --target typescript --localSchemaFile src/code/queries/schemas/schema.json  --outputFlat src/code/queries/generated
  </code></pre>
  
  <p>the globalTypes.ts is generated empty (only comments)..</p>