Update Montana Tax Logic

[finpaul]

• make format and make documentation has been run. (You may also want to run make test.)

This PR adds the Montana tax logic to FiscalSim-US @rickecon

[codecov]

Codecov Report

Attention: 35 lines in your changes are missing coverage. Please review.

Comparison is base (8d3baf3) 98.57% compared to head (a470425) 98.45%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
...s/itemized/mt_medical_dental_expenses_deduction.py	64.28%	5 Missing ⚠️
...gov/states/mt/tax/income/main/mt_taxable_income.py	64.28%	5 Missing ⚠️
...s/itemized/mt_political_contributions_deduction.py	69.23%	4 Missing ⚠️
...eductions/itemized/mt_state_local_tax_deduction.py	69.23%	4 Missing ⚠️
...come/credits/mt_tax_after_nonrefundable_credits.py	75.00%	3 Missing ⚠️
...iables/gov/states/mt/tax/income/main/mt_tax_due.py	75.00%	3 Missing ⚠️
...s/gov/states/mt/tax/income/main/mt_tax_overpaid.py	75.00%	3 Missing ⚠️
...ncome/deductions/itemized/mt_casualty_deduction.py	81.81%	2 Missing ⚠️
...eductions/itemized/mt_charitable_cash_deduction.py	83.33%	2 Missing ⚠️
...ctions/itemized/mt_charitable_noncash_deduction.py	81.81%	2 Missing ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #58      +/-   ##
==========================================
- Coverage   98.57%   98.45%   -0.12%     
==========================================
  Files        1773     1802      +29     
  Lines       26410    26697     +287     
  Branches      142      142              
==========================================
+ Hits        26033    26285     +252     
- Misses        346      381      +35     
  Partials       31       31              

Flag	Coverage Δ
unittests	98.45% <88.01%> (-0.12%)	⬇️

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[rickecon]

@finpaul. We don't want to change the fiscalsim_us/data/geography/zip_codes.csv.gz.