feat: add PR author fallback for contributor tagging

[PKief]

Enhances contributor attribution by adding a fallback mechanism that uses GitHub PR author information when email-to-username resolution fails.

Resolves #116

Changes

• Added getPullRequestAuthorLogin() function in github.ts to fetch PR author details
• Enhanced generateMarkDown() in markdown.ts with PR author fallback logic
• Added helper function getAuthorPRNumber() to extract PR numbers from commit references

Benefits

• Better contributor attribution in changelogs
• Fallback mechanism for private email addresses
• No breaking changes to existing functionality

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 60.03%. Comparing base (0914fd7) to head (23dc19e). :warning: Report is 81 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #294      +/-   ##
==========================================
- Coverage   69.10%   60.03%   -9.07%     
==========================================
  Files           9       12       +3     
  Lines         916     1046     +130     
  Branches       85      148      +63     
==========================================
- Hits          633      628       -5     
- Misses        283      416     +133     
- Partials        0        2       +2     

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[PKief]

Hi @pi0, I've added some additional unit tests to increase the coverage. Unfortunately, I'm not exactly sure why the codecov check is still failing. It compares my changes with some commit made one year ago: https://github.com/unjs/changelogen/commit/0914fd7 This commit is not even the latest one on the main branch.

Do you have any idea how I can get this PR in?

[pi0]

It looks a very good PR dear @PKief. I'm little bit occupied to do final review/merge/releases.

Will do as soon as could.