feat(core): use git config to determine author before username

[pd4d10]

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

This PR use git config to determine author before username. Since git repository has been initialized before initializing npm, we could get git author name and email.

[malept]

Can you please describe your use case in the pull request summary (under "Summarize your changes")?

[malept]

Also, the commit message should be feat(core): use git config to determine author before username (note that it's core instead of cli).

[pd4d10]

@malept , Thanks for the suggestion. Issues resolved and pushed.

The only thing I'm not sure is whether to use name <email> or object pattern. Seems npm init and yarn init both use name <email>. Could you confirm it again?

[malept]

The only thing I'm not sure is whether to use name <email> or object pattern. Seems npm init and yarn init both use name <email>. Could you confirm it again?

It makes sense that those init subcommands use the string version, because it uses interactive prompts to get the author data. This is doing it programmatically, so we don't need to have the package manager parse strings.

[malept]

I did some refactors on the code, but I think the last thing it needs are some tests.

I made a bunch of changes

[malept]

@MarshallOfSound could you take a look at this before it gets merged? The tests could probably be written better.

Applied change as requested