GitBook-specific syntax in README doesn’t render correctly on GitHub

## Documentation issue

Hi 👋,

I noticed that the [README.md](https://github.com/i18next/react-i18next-gitbook) contains GitBook-specific syntax blocks such as

{% hint style="info" %} ... {% endhint %}
{% hint style="warning" %} ... {% endhint %}
{% embed url="..." %}

## Motivation

These render fine in GitBook but appear as raw text on GitHub, which may confuse readers who view the project directly here.