github api throttling

[elkh510]

Firstly - great plugin :)

Version report

Jenkins and plugins versions report:

jenkins - 2.263.4 
Job and Stage monitoring Plugin - 3.6.2

• What Operating System are you using (both controller, and any agents involved in the problem)?

use docker image
jenkins/jenkins:2.263.4-lts-jdk11

Reproduction steps

• jenkins job use in scm github-app(instead of github user), but github-autostatus-plugin can't use github-app and we get limit in 5000 call per hour(limit for github-app 15000 call per hour). because of github api Throttling hooks do not send to github and checks are not marked as passed and there is no way to merge pr.

Please add ability to use github-app instead of github-user
and ability to specify a separate github-app for auth in the plugin.
thank you!

[samrocketman]

It already supports github app. There is a bug, though. #115