Stop using pysha3

[0-wiz-0]

According to its github README, pysha3 was only ever for python versions before 3.6 and after that, the hashlib module should be used. Please do that :)

To quote https://github.com/tiran/pysha3:

The pysha3 package has reached its end of life and is no longer supported.

The SHA-3 code was merged into Python 3.6 many years ago. Please use SHA-3 functions from [hashlib](https://docs.python.org/3/library/hashlib.html) module directly.

[elopez]

Thanks for the report! Indeed, we're looking to migrate away from pysha3 across several of our tools. The hashlib module does not offer keccak256 hashes (which pysha3 did) so we're moving to pycryptodome instead.

Related: crytic/crytic-compile#309, crytic/solc-select#128, crytic/slither#1454

[0-wiz-0]

Looks like you're well on your way already, great!