GethPOAMiddleware is not correctly applied to Polygon POS mainnet and Polygon Amoy testnet

[zomglings]

Environment information

• brownie Version: 1.20.2
• Python Version: 3.12.3
• OS: osx

What was wrong?

The GethPOAMiddleware.get_layer method runs w3.eth.get_block(0), which doesn't error out on Polygon mainnet and the Amoy testnet.

How can it be fixed?

Changing the check to w3.eth.get_block("latest") resulted in the error being fixed.

There were previously issues with people using Ganache forks of these networks, though, which added blocks that didn't cause errors, which seems to be why the code was changed to look up 0, and which is why I haven't made a PR: #1217

Maybe switching to some other block would work?

[iamdefinitelyahuman]

Perhaps use "latest" when connected to a live network, and use 0 when on a development network.