bump web3 to latest version

[oveddan]

Description

Bumps the supported web3.py version to the latest: 6.7.0

Motivation and Context

Projects that import this project are forced to use a previous version of web3.py which doesn't have async support for contracts.

How has this been tested?

Ran unit tests

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.