Update README.md, use redis discord guild

[ndyakov]

There is a Redis Discord guild and there is a channel for go-redis that can be utilized by contributors.

[ndyakov]

@elena-kolevska do you think it would be beneficial to point contributors to Redis Discord guild? It is not widely used, but I can see @tishun was active once in it, I am checking it from time to time.

[elena-kolevska]

@elena-kolevska do you think it would be beneficial to point contributors to Redis Discord guild? It is not widely used, but I can see @tishun was active once in it, I am checking it from time to time.

Definitely! Let's also link to the spefific channel (#go-redis-contributors).

Please also make sure to enable notifications for this channel in your Discord @ndyakov, @ofekshenawa , @htemelski.

[tishun]

FWIW you might consider adding the other banners from other driver projects, e.g. license, twitch x, stackoverflow, etc.

For example see the node-redis, lettuce, etc.

I was thinking we should standardize the way the header of each driver README looks like, but we haven't discussed it