Add parameters for QBI deduction phaseout

[Peter-Metz]

This PR adds two parameters to model a phaseout of the QBI deduction, PT_qbid_ps and PT_qbid_prt, based on taxable income.

Biden has proposed a phaseout of the QBI deduction for those with taxable income > $400,000, although he has not specified the phaseout rate.

Since the wage and capital restrictions are fully enforced in Tax-Calculator for all taxpayers (see #2385 and PSLmodels/taxdata#319), implementing Biden's phaseout has little revenue effect.

[codecov]

Codecov Report

Merging #2508 (42fd3b0) into master (d3c7037) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2508   +/-   ##
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  Coverage   99.92%   99.92%           
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  Files          13       13           
  Lines        2591     2591           
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  Hits         2589     2589           
  Misses          2        2           

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[MattHJensen]

@Peter-Metz, thanks a lot for this PR. There are conflicts now, so I added back the WIP label.

Do you think compatible_data should be set to false since these don't really work with puf and cps files?

[Peter-Metz]

@MattHJensen the latest commit should resolve the conflicts.

Do you think compatible_data should be set to false since these don't really work with puf and cps files?

Hmm, I'm not sure why the phaseout wouldn't work with the puf and cps. The only inputs needed to compute the phaseout are the amount of qbid and pre-qbid taxable income. What do you think?

[MattHJensen]

Hmm, I'm not sure why the phaseout wouldn't work with the puf and cps. The only inputs needed to compute the phaseout are the amount of qbid and pre-qbid taxable income. What do you think?

Yes, that makes sense to me now. Thanks a lot for the PR! Merging.