github api for update blog

[huming0618]

• https://developer.github.com/v3/git/refs/#create-a-reference
• https://stackoverflow.com/questions/20045572/create-folder-using-github-api
• https://developer.github.com/v3/git/trees/
• http://www.levibotelho.com/development/commit-a-file-with-the-github-api/
• https://medium.freecodecamp.org/pushing-a-list-of-files-to-the-github-with-javascript-b724c8c09b66

[huming0618]

gridea use simple-git https://github.com/getgridea/gridea/blob/0e0a19c831d71e68f6dd0c178d7638e721033c28/src/background.ts