Add ERC20TransferEvent and ERC721TransferEvent models

[chaoyaji-cb]

What changed? Why?

• Add ERC20TransferEvent and ERC721TransferEvent models for webhook event parsing
• Minor comment update on event filter

Qualified Impact

[alex-stone]

Awesome! Can we add utilities to parse the events in the context of a Webhook Handler?

E.g. I am implementing a Webhook Handler, I have a payload, how to I parse this payload of unknown type into one of these?

event = Webhook::Event.from_payload(payload)

Or something like:

>event = Webhook::Event.build(payload)
>puts event.type
=> "erc20-transfer"

Here is an example handler example: https://docs.stripe.com/webhooks/quickstart?lang=ruby

We can add docs for how to build a simple handler in each language, but for the context of the SDK we'd like to be able to easily parse raw data into these models!