Incubator-mxnet: [CI] How to restart a single stage on MXNet CI?

[wkcn]

Hi, there.

Sometimes, due to strage reason, the CI test fails, but it may be not relevant to the PR.

There are many PRs failing only a check because of strage reason. As we know, it will cost a lot of money and take a long time to restart all stages : (

It will be economic and convenient if it is available to restart a single stage on MXNet CI.

[leezu]

@ChaiBapchya is working to provide this feature for the github bot

[wkcn]

The problem has been solved : )