Vouch doesn't set correct validator_index when calling /eth/v1/validator/beacon_committee_subscriptions`

[sauliusgrigaitis]

We testing Grandine Beacon Node API with Vouch and we found that Vouch doesn't set correct validator_index when calling /eth/v1/validator/beacon_committee_subscriptions:

"level":"trace","service":"client","impl":"http","id":"4c4079f1","address":"localhost:9301","endpoint":"/eth/v1/validator/beacon_committee_subscriptions","body":"[{"validator_index":"0","slot":"482059","committee_index":"12","committees_at_slot":"25","is_aggregator":false},{"validator_index":"0","slot":"482074","committee_index":"18","committees_at_slot":"25","is_aggregator":false},{"validator_index":"0","slot":"482073","committee_index":"10","committees_at_slot":"25","is_aggregator":false},...

Grandine doesn't like it as it checks that the validator is actually in the committee.

[mcdee]

I tested this against a different beacon node and it appears to be sending the correct validator indices:

[{"validator_index":"985","slot":"499121","committee_index":"0","committees_at_slot":"1","is_aggregator":false},{"validator_index":"913","slot":"499128","committee_index":"0","committees_at_slot":"1","is_aggregator":false},...]

which suggests that it is an issue with a different call. Please could you run vouch with the following additional configuration:

eth2client:
  log-level: trace

and send over the log file? This should give a bit more information to help track down the issue.

[mcdee]

Fixed in #94