feat(git): add merge filter options

[samydoesit]

Added filtering options for merge commits.

I attempted to add tests and a reproduction but was unsure how to make it.
If something is missing or needs to be changed please let me knkow.

resolves #62

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 12 lines in your changes missing coverage. Please review.

Project coverage is 44.70%. Comparing base (0914fd7) to head (b098084).
Report is 43 commits behind head on main.

Files with missing lines	Patch %	Lines
src/commands/default.ts	0.00%	8 Missing ⚠️
src/git.ts	60.00%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #241       +/-   ##
===========================================
- Coverage   69.10%   44.70%   -24.40%     
===========================================
  Files           9       12        +3     
  Lines         916      964       +48     
  Branches       85       97       +12     
===========================================
- Hits          633      431      -202     
- Misses        283      530      +247     
- Partials        0        3        +3     

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