Update project rxjs to v2.3.13

libgrabber updated project rxjs to v2.3.13.

@Reactive-Extensions

### Metadata information

```json
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    "packageManager": "github",
    "name": "rxjs",
    "repo": "Reactive-Extensions/RxJS",
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      "basePath": "dist/",
      "include": ["*.js"],
      "exclude": []
    },
    "path": "/home/jsdelivr/files/rxjs",
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    "branchVersions": []
  },
  "version": "v2.3.13",
  "updated": true,
  "updatePath": "/home/jsdelivr/files/rxjs/2.3.13",
  "branch": "rxjs/v2.3.13"
}
```