RedisStore should target official implementation

[QEDK]

The unofficial fastify-session package is being brought back to life officially Currently, a lot of packages such as grant target the unofficial package and will theoretically move to the newer one, ideally I can see this being a super-useful plugin if it maintains compatibility with the official session package. In my specific case, I tried to use this with grant but since it doesn't maintain cookie compatibility, I couldn't get it to work.