Add Antelope BlockHeaderExtension

[DenisCarriere]

To add

• decoded_header_extensions
  • ProtocolFeatureActivationExtension
  • ProducerScheduleChangeExtension

message BlockHeader {
  google.protobuf.Timestamp timestamp = 3;
  string producer = 4;
  uint32 confirmed = 5; // uint16
  string previous = 6;
  bytes transaction_mroot = 7;
  bytes action_mroot = 8;
  uint32 schedule_version = 9;
  repeated Extension header_extensions = 11;
  repeated BlockHeaderExtension decoded_header_extensions = 12;

  // EOSIO 1.x only
  //
  // A change to producer schedule was reported as a `NewProducers` field on the
  // `BlockHeader` in EOSIO 1.x. In EOSIO 2.x, when feature `WTMSIG_BLOCK_SIGNATURES`
  // is activated, the `NewProducers` field is not present anymore and the schedule change
  // is reported through a `BlockHeaderExtension` on the the `BlockHeader` struct.
  //
  // If you need to access the old value, you can
  ProducerSchedule new_producers_v1 = 10;
}

message BlockHeaderExtension {
  oneof extension {
    ProtocolFeatureActivationExtension protocol_feature_activation_extension = 1;
    ProducerScheduleChangeExtension producer_schedule_change_extension = 2;
  }
}
message ProtocolFeatureActivationExtension {
  repeated bytes protocol_features = 1;
}

message ProducerScheduleChangeExtension {
  ProducerAuthoritySchedule producer_schedule = 1;
}
message ProducerAuthoritySchedule {
  uint32 version = 1;
  repeated ProducerAuthority producers = 2;
}

// Present in EOSIO 2.x only
message ProducerAuthority {
  string account_name = 1;
  BlockSigningAuthority block_signing_authority = 2;
}