Add Attestation Types

[hoani]

Attestation types are missing. We should add them since Attestation belongs to Pl^g

It works if I add:

const api = await ApiPromise.create({
  provider,
  types: {
    ...PlugRuntimeTypes.default,
    AttestationTopic: 'U256',
    AttestationValue: 'U256',
  }
});