feat: replaces usages of deprecated eth_abi package methods

[mbaranovski]

What I did

Running tests using brownie outputs lots of eth-abi package deprecation warnings like:

DeprecationWarning: abi.encode_abi() and abi.encode_abi_packed() are deprecated and will be removed in version 4.0.0 in favor of abi.encode() and abi.encode_packed(), respectively.

Source: https://github.com/ethereum/eth-abi/blob/v2.2.0/eth_abi/abi.py#L11
This PR addresses fixes the warnings.

How I did it

Replaces deprecated methods:

• encode_abi -> encode
• decode_abi -> decode

How to verify it

Run the tests using brownie.network.contract functionality and notice lack of above warnings.

Checklist

• I have confirmed that my PR passes all linting checks
• I have added an entry to the changelog

[mbaranovski]

Hi @iamdefinitelyahuman, that's a small PR do you think we can merge it? Thanks!

[sreyemnayr]

I see this was merged but am still getting these warnings in 1.19.3 - anyone else?

[cheewen-ho]

I see this was merged but am still getting these warnings in 1.19.3 - anyone else?

me too...
Have you found a solution?