message: Fix round_participation
  If the latest vote is before the beginning of the round, then the
  validator didn't participate in the round, so `No` should be returned.
diff: @@ -395,7 +395,13 @@ fn round_participation<'a, C: Context>(
  };
  match opt_vote {
  None => RoundParticipation::No,
  - Some((vh, vote)) if vote.round_exp <= r_id.trailing_zeros() => RoundParticipation::Yes(vh),
  + Some((vh, vote)) if vote.round_exp <= r_id.trailing_zeros() => {
  + if vote.timestamp >= r_id {
  + RoundParticipation::Yes(vh)
  + } else {
  + RoundParticipation::No
  + }
  + }
  Some((_, _)) => RoundParticipation::Unassigned,
  }
  }
  