feat: after running `package create manuscript`, create a GitHub repo and link the local one via GitHub API.

[ycexiao]

Problem

After creating a manuscript local project, users need to manually create a GitHub repo and link the local one to it to continue the work in Overleaf. We want to let scikit-package-manuscript automate this process.

Proposed solution

Use the GitHub API in the post hook to automatically create a GitHub repo and link the local one.