fga --version should return the version of the OpenFGA server

[aaguiarz]

If the CLI is configured to use an OpenFGA server, the fga --version command should also return the server version.

If the OpenFGA server does not expose that endpoint for some reason, it should display unknown

$ fga --version

fga CLI version v`0.2.6` (commit: `dc4e39648ec5b626fc5c44c4f9f77a1e15806ab7`, date: `2024-02-28T12:47:25Z`)
openfga version v`1.5.0`

[Siddhant-K-code]

To implement this, we need a server endpoint that returns the OpenFGA server version in a JSON response. Do we have an endpoint like https://api.us1.fga.dev/version (API Url is a example taken from readme) that returns a JSON response similar to this?

{
  "version": "v1.5.0"
}