Add `StorageChange.oldValue`
Add previous old value of the contrat's storage to StorageChange
.
Suggested code:
// Get from somewhere e.g. add it to `indexingContext`.
const previousBlockHash = ...
// Beware that big maps could be treated differently from `contract.getStorage()`.
const oldStorage = await this.taquitoToolkit.rpc.getStorage(contract.address, { block: previousBlockHash });