Search an external skill source

{  "items": [    {      "source": "registry",      "ref": "string",      "name": "string",      "description": "string",      "type": "project",      "version": "string",      "deprecated": {        "at": "2019-08-24T14:15:22Z",        "message": "string"      },      "installs": 0    }  ],  "nextCursor": "string"}

{  "defined": true,  "code": "UNAUTHORIZED",  "status": 401,  "message": "Authentication required or credentials invalid.",  "data": null}

{  "defined": true,  "code": "VALIDATION",  "status": 422,  "message": "The input failed domain validation.",  "data": {    "issues": [      {        "path": "string",        "message": "string"      }    ]  }}

{  "defined": true,  "code": "RATE_LIMITED",  "status": 429,  "message": "Rate limit exceeded; retry later.",  "data": {    "retryAfterSeconds": -9007199254740991  }}

{  "defined": true,  "code": "UPSTREAM_UNAVAILABLE",  "status": 502,  "message": "The external source could not be reached.",  "data": {    "source": "string",    "reason": "unauthorized"  }}