Update project pixi.js to v2.1.1

libgrabber updated project pixi.js to v2.1.1.

@GoodBoyDigital

### Metadata information

```json
{
  "metadata": {
    "packageManager": "github",
    "name": "pixi.js",
    "repo": "GoodBoyDigital/pixi.js",
    "files": {
      "basePath": "bin/",
      "include": ["pixi.js"],
      "exclude": []
    },
    "path": "/home/jsdelivr/files/pixi.js",
    "localVersions": ["1.5.2", "1.5.3", "2.0.0", "2.1.0"],
    "remoteVersions": ["v1.1.0", "v1.2.0", "v1.3.0", "v1.4.0", "v1.4.1", "1.4.2", "v1.4.2", "v1.4.3", "v1.5.0", "v1.5.1", "v1.5.2", "v1.5.3", "v1.6.0", "v1.6.1", "v2.0.0", "v2.1.0", "v2.1.1"],
    "branchVersions": []
  },
  "version": "v2.1.1",
  "updated": true,
  "updatePath": "/home/jsdelivr/files/pixi.js/2.1.1",
  "branch": "pixi.js/v2.1.1"
}
```