fix: update repository URLs in package.json

[dudeofawesome]

Fixing the repo & homepage links on the google-auth-library npm package.

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[gemini-code-assist]

Code Review

This pull request updates the repository directory, repository URL, and homepage URL in the package.json of google-auth-library-nodejs to reflect its new location in the monorepo. There are no review comments, and I have no feedback to provide.

[macastelaz]

Thanks!

[pearigee]

Would you mind amending your commit message to match the PR title?
"fix: update repository URLs in package.json"

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