fix: use commit-to-co-authors and co-author-to-username

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes 🐛 Bug: Invalid contributor parsed for a co-author attribution #33
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Uses two new packages of mine for better email/username collection and parsing:

• https://github.com/JoshuaKGoldberg/commit-to-co-authors: standalone parser for taking co-author(s) email, name, and/or username object(s) from commits.
• https://github.com/JoshuaKGoldberg/co-author-to-username: standalone fetcher for GitHub users from their email or username.

[codecov]

Codecov Report

Attention: 6 lines in your changes are missing coverage. Please review.

Comparison is base (b071866) 44.65% compared to head (d8caf6d) 41.81%.
Report is 46 commits behind head on main.

Files	Patch %	Lines
src/collect/index.ts	0.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #160      +/-   ##
==========================================
- Coverage   44.65%   41.81%   -2.84%     
==========================================
  Files          16       14       -2     
  Lines         486      452      -34     
  Branches       19       14       -5     
==========================================
- Hits          217      189      -28     
+ Misses        269      263       -6     

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