Rename GitHubApi to Octokit

[ajsb85]

Hi, @miyajan

I updated the repository using the new package for GitHub API REST.

Reference: #1

[miyajan]

Thank you for your pull request. But npm run build causes an error.

$ npm run build

> [email protected] build /Users/miyajan/project/node-github-release
> tsc

node_modules/@octokit/rest/index.d.ts:5:1 - error TS1084: Invalid 'reference' directive syntax.

5 /// <reference lib="esnext.asynciterable" />
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! [email protected] build: `tsc`
npm ERR! Exit status 2
npm ERR! 
npm ERR! Failed at the [email protected] build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/miyajan/.npm/_logs/2019-07-28T14_05_11_681Z-debug.log

It seems that the typescript's version is too older for the latest Octokit. Could you fix it? Or should I fix it?

[miyajan]

octokit/rest.js@1fff810
And some methods are renamed. They must be fixed.

[ajsb85]

Hi, @miyajan
I will work on it very soon.
Thank you very much for the review.