Add subscriber for check run event in order to handle rerun request

[XiongKezhi]

For the request payload example, see https://github.com/jenkinsci/github-checks-plugin/blob/8273ee1bc151e0b1b94bfa9a5a9d8e88c3e29b7f/src/test/resources/io/jenkins/plugins/checks/github/CheckRunGHEventSubscriberTest/check-run-event-with-rerun-action.json

[timja]

so do we need this method? seems like it should be available?

[XiongKezhi]

this method is available, but using the object from github-api is better since we don't have to parse the json again, and more safe.

the github-api has released 1.116, may just need to wait two or three days, the github-api-plugin will follow up

[timja]

kk

[XiongKezhi]

The next step: in checks-api, add the "rerun" action in the listener for the main build when completed.

[XiongKezhi]

I think we have talked about this in community boding but I forgot when starting this PR: I found that when a check fails, a rerun bottom will be automatically added by github like this:

So this is different from what I was thinking before (the action in the checks API, which is added by user request regardless the check resule)

I think it make more sense that we support the the github one instead of the requested one, I'll change to that, nothing different but the 'action' field in the webhook payload.

[codecov]

Codecov Report

Merging #25 into master will increase coverage by 1.98%.
The diff coverage is 90.56%.

@@             Coverage Diff              @@
##             master      #25      +/-   ##
============================================
+ Coverage     77.33%   79.32%   +1.98%     
- Complexity       96      112      +16     
============================================
  Files             7        8       +1     
  Lines           300      353      +53     
  Branches         33       39       +6     
============================================
+ Hits            232      280      +48     
- Misses           48       53       +5     
  Partials         20       20              

Impacted Files	Coverage Δ	Complexity Δ
...ugins/checks/github/CheckRunGHEventSubscriber.java	90.56% <90.56%> (ø)	16.00 <16.00> (?)

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