Add SNAP minimum benefit

[nmrodelo]

Draft/ work in progress pull request for snap minimum benefit parameters

[MaxGhenis]

I know just a draft but a couple comments after checking it out

[MaxGhenis]

I'm not sure why relevant_max_benefit is null in the calculation. @nikhilwoodruff any ideas?

https://github.com/PolicyEngine/openfisca-us/runs/4419215730?check_suite_focus=true#step:5:591

[nmrodelo]

@nikhilwoodruff could you take a look at this?

[nikhilwoodruff]

Just took a look @nmrodelo - it's what I think is a bug in Core (I've seen it before in a few places). Essentially, when we index a parameter with an array of numbers (e.g. amount_by_household_size[[1, 1, 1, 3, 1, 2]]) we get the right values, but when we index by just a single number (amount_by_household_size[1]) it doesn't seem to work - except when we do amount_by_household_size["1"]. Here's how I fixed it locally below.

[nmrodelo]

@nikhilwoodruff is there anything left on my end for this PR?

[MaxGhenis]

Try renaming snap_min_benefit to snap_minimum_benefit in snap.py

[MaxGhenis]

Please also rename the test file to snap_minimum_benefit.yaml to match the variable name.

[codecov]

Codecov Report

Merging #315 (d1b7e8b) into master (39a24df) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #315   +/-   ##
=======================================
  Coverage   94.87%   94.88%           
=======================================
  Files          59       59           
  Lines        3652     3654    +2     
  Branches      480      480           
=======================================
+ Hits         3465     3467    +2     
  Misses        162      162           
  Partials       25       25           

Impacted Files	Coverage Δ
openfisca_us/variables/usda/snap/snap.py	100.00% <ø> (ø)
openfisca_us/variables/usda/snap/min_benefit.py	100.00% <100.00%> (ø)

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[MaxGhenis]

Thanks @nmrodelo, could you just do two more things? We're trying to get back on the http://semver.org track. You'll have to pull to fetch my latest PR.

1. Update the version to 0.4.0 in setup.py (this PR adds new functionality, so it's a minor change rather than patch)
2. Update CHANGELOG.md with an entry for 0.4.0 saying Add SNAP minimum benefit

I'll merge from there.

[nikhilwoodruff]

Looks great, thanks @nmrodelo. The semantic versioning GH action now looks like it's working (see the error message) - could you just add to the CHANGELOG.md (referencing this #315 PR like the openfisca one)? Looks good to merge straight after that

[nikhilwoodruff]

@nmrodelo thanks for this PR! Just added the changelog entry, merging.