The original motivation for keeping type checking in the default
environment is so that it can be executed from the `github` and `local`
environments. Otherwise, it would not be possible to run type checks
in those environments against the correct version of autonity.py. This
restores `check-types` to the default environment, partially reverting
the change in e74d922.

This would be how to run type checks in the `github` environment:

```
hatch env prune
export AUTPY_GIT_COMMIT=...
hatch env create github
hatch -e github run pip freeze | grep autonity # verify correct
hatch run github:check-types
```

The `tx make --legacy` option does not do what it says, because `tx
make` adds `maxFeePerGas` and `maxPriorityFeePerGas` to the transaction
params, negating the option, and forcing it to become a TransactionType
0x2 instead.

In order to force a LegacyTransaction as per EIP-2718, set the
`--gas-price` instead, which matches the logic used and expected by
web3.py itself.