feat: implement enhanced 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, Follow up of #294

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

[PKief]

Just opened this one to double check if codecov is getting green on a fresh PR, didn't work - closing again. Please apologize for the spam.