Add WOFF2 version

Generated from the 160 KB TTF version using the following command:

```bash
curl --data-binary '@/tmp/grumpy.ttf' -o 'grumpy.woff2' -H 'Content-Type: font/ttf' -H 'Accept: font/woff2' -X 'POST' 'http://188.226.250.76/'
```

Note: the WOFF2 version is only 20K.

See https://gist.github.com/sergejmueller/cf6b4f2133bcb3e2f64a for more info on WOFF2.