fix(plugin): fetch with credentials for same origin request

[yaeda]

When the plugin option is private: true and the document site has authentication, fetching local contents doesn't work. I added { credential: "same-origin" } to fetch local contents.

Sorry for my frequent PRs. Should I have created a new plugin myself 😕 ?

[azu]

Sorry for my frequent PRs. Should I have created a new plugin myself 😕 ?

No problem.
I've invited @yaeda as collaborators in this repository.
Also, I've added to npm too 😃

Feel free to develop this plugin!
Of course, I will review if necessary.
(Feel free to assign Reviewers)

[azu]

Relase 1.3.2

Publish log

npm test # but this plugin have not test yet
npm version patch
npm publish

[yaeda]

Wow, Thank you very much for the invitation. I accepted!