Yubikey advatanges should be a list too

https://github.com/DefGuard/docs/blob/fc77a89cf677f97369c4e57b18e97a50468d8e49/README.md?plain=1#L78C12-L78C12

As far as other points are bullet-ins, don't you think it's better to make bulletin here too?

<img width="1051" alt="image" src="https://github.com/DefGuard/docs/assets/29892471/b577d0bf-64d4-4dd7-82ea-330998f13b6b">
