fix Project openapi spec (#143)

The current output is the following:

```
$ --> curl http://localhost:8081/api/v1/workspaces/b89dbbbd-0d9c-4fd3-965f-de94b5d9974c/projects/b013587c-06a9-45a7-a6b2-32c5259a356f  | jq .
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   778  100   778    0     0   364k      0 --:--:-- --:--:-- --:--:--  759k
{
  "id": "b013587c-06a9-45a7-a6b2-32c5259a356f",
  "name": "WorkFlowID: 7ee4b05b-1bad-43d7-a121-a48082b1e108",
  "description": "Project for workflow: 7ee4b05b-1bad-43d7-a121-a48082b1e108",
  "timestamp": "2023-05-22T09:01:36.768895805Z",
  "inputs": {
    "9c0fe7fa-84ee-4cc5-b66b-dee164528f03": {
      "id": "9c0fe7fa-84ee-4cc5-b66b-dee164528f03",
      "name": "output.zip",
      "description": "bar",
      "timestamp": "2023-05-22T09:01:37.622315731Z",
      "type": "sources",
      "normalized_name": "output"
    }
  },
  "outputs": {
    "25af2abc-2d78-466b-b63c-063796acb286": {
      "id": "25af2abc-2d78-466b-b63c-063796acb286",
      "name": "25af2abc-2d78-466b-b63c-063796acb286",
      "description": "",
      "timestamp": "2023-05-22T09:01:38.673085959Z",
      "status": "done"
    }
  },
  "status": {
    "outputs": true,
    "plan": true,
    "plan_error": false,
    "planning": false,
    "sources": true,
    "stale_plan": false
  }
}
```

Signed-off-by: Eloy Coto <eloy.coto@acalustra.com>

assets/openapi.json

@@ -2342,6 +2342,31 @@
             "type": "string",
             "format": "date-time"
           },
+          "outputs": {
+            "type": "object",
+            "additionalProperties": {
+              "type": "object",
+              "properties": {
+                "id": {
+                  "type": "string",
+                  "format": "uuid"
+                },
+                "name": {
+                  "type": "string"
+                },
+                "description": {
+                  "type": "string"
+                },
+                "timestamp": {
+                  "type": "string",
+                  "format": "date-time"
+                },
+                "status": {
+                  "type": "string"
+                }
+              }
+            }
+          },
           "status": {
             "type": "object",
             "properties": {