feat: added Optimism and Arbitrum support (updated constants.py)

[liquid-8]

Closes #185
Closes #183
Closes #176

[romanbsd]

Also 421611 => "arbitrum_testnet"

[romanbsd]

BTW, I'm using uniswap-python on arbitrum, and I had to monkey patch _get_tx_params and remove the "gas" parameter, otherwise I was receiving "insufficient funds for gas". Perhaps it's something specific to my setup, but I thought that it might be useful for others if they also face such problem.

[liquid-8]

I've checked some uni swaps on arbitrum and it turns out txn requires gas spendings ~1m but _get_tx_param has hardcoded 250k limit. So I'm quite sure it isn't about your setup.

[romanbsd]

Yes, I can testify: 1,078,834
I wasn't sure that it's not something specific to my case. I'm curious why it's different from L1 gas usage.

[ErikBjare]

BTW, I'm using uniswap-python on arbitrum, and I had to monkey patch _get_tx_params and remove the "gas" parameter, otherwise I was receiving "insufficient funds for gas".

Perhaps the gas parameter could be removed entirely from _get_tx_params? Perhaps we should use estimate_gas instead?

I wasn't sure that it's not something specific to my case. I'm curious why it's different from L1 gas usage.

Could it be because each LP position is smaller, and this impacts gas efficiency? (just guessing) Edit: Nevermind, answers here https://developer.offchainlabs.com/docs/arbgas

[ErikBjare]

Merging this for now, we'll deal with any issues in future PRs.

[romanbsd]

Uniswap3 suggest doing 1.2 * estimateGas. I can make a PR if you want.

[ErikBjare]

@romanbsd That would be appreciated :)