Update project uikit to 2.15.0

libgrabber updated project uikit to 2.15.0.

@uikit

### Metadata information

```json
{
  "metadata": {
    "packageManager": "github",
    "name": "uikit",
    "repo": "uikit/bower-uikit",
    "files": {
      "include": ["./css/**/*.min.css", "./fonts/**/*", "./js/**/*.min.js"],
      "exclude": []
    },
    "path": "/home/jsdelivr/files/uikit",
    "localVersions": ["2.3.0", "2.3.1", "2.4.0", "2.5.0", "2.6.0", "2.7.1", "2.8.0", "2.9.0", "2.10.0", "2.12.0", "2.13.0", "2.13.1", "2.14.0"],
    "remoteVersions": ["2.11.0", "2.11.1", "2.12.0", "2.13.0", "2.13.1", "2.14.0", "2.15.0"],
    "branchVersions": []
  },
  "version": "2.15.0",
  "updated": true,
  "updatePath": "/home/jsdelivr/files/uikit/2.15.0",
  "branch": "uikit/2.15.0"
}
```