Are we computing the Colorado CCAP parent fee correctly?

[MaxGhenis]

I haven't dug into the details of how it's calculated, but I don't think it should be zero even when there's a $100,000 child care expense, as in this example, where as a result the CCAP subsidy is the full $100k until they hit the cliff. So I think there's a bug in the parent fee computation.

We should add integration tests that include a household where the parent fee binds: https://github.com/PolicyEngine/policyengine-us/tree/master/policyengine_us/tests/policy/baseline/gov/states/co/ccap

[MaxGhenis]

Looking more closely at the co_ccap_parent_fee unit test, Python code, and parameter files, I got a parent fee to exist for a household with 8 hours of child care per day.

I'm now less confident this is a bug, so converting to a discussion, though I've filed a couple cleanup issues that would give greater confidence in the code:

• Add Colorado CCAP integration tests #3618
• Refactor co_ccap_parent_fee code #3619