Upgrade to python 3.11

[nutrina]

Then we would be able to use: https://docs.python.org/3/library/datetime.html#datetime.datetime.fromisoformat
for parsing multiple formats of iso dates.

[nutrina]

Support for python 3.11 might not yet be available for siwe and web3: ethereum/web3.py#2704

We might need an alternative to parsing the iso dates.

[erichfi]

Whoever picks this, make sure web3 works on this Python version.

[aminah-io]

Looks like they added support for python 3.11 with this PR: ethereum/web3.py#2699

[nutrina]

Yes, that right, python 3.11 seems to be officially supported, it is listed here: https://pypi.org/project/web3/6.0.0/