Missing `events` feature gating with error variant in `eth2` package

[mempirate]

lighthouse/common/eth2/src/error.rs

Line 105 in edba56b

Error::SseEventSource(_) => None,

This is missing the event feature gating, so it fails compilation

[michaelsproul]

Sorry for the oversight. This is fixed on unstable:

• Fix eth2 compilation by feature gating SseEventSource #8819

We are about to cut v8.1.1 but at this stage it doesn't include this fix. Do you want us to cherry-pick it over or are you fine enabling the feature for now/using unstable?

[mempirate]

Ty for the prompt reply! I'm just enabling the feature right now so no need to cherry pick just for my use case