web3.py v7 middleware

Quick syncronous and asynchronous examples of the middleware pattern introduced in v7 of web3.py.

To run the examples:

• install deps: pip install web3==v7.0.0b2 python-dotenv
• add your RPC URL to the .env file
• run either python sync.py or python async.py

If you want to skip all that, sample console output is included at the bottom of each file.