When rebasing an accepted PR lgtm requires another webhook call to update

[frapposelli]

Steps to reproduce:

• Open a PR
• LGTM it (status check turns green)
• Rebase and (force) push to fork
• Status check is reset
• Add a comment (not necessary a LGTM)
• Status check turns green again.

What I'd like to happen:

• Open a PR
• LGTM it (status check turns green)
• Rebase and (force) push to fork
• Status check is still green

[bradrydzewski]

At first glance I'm guessing GitHub must reset the status checks because LGTM doesn't receive pull_request hooks, only issue hooks. Will have to dig deeper though to fully understand

[aaronjensen]

I just pushed a new commit, didn't even rebase and it didn't update status until I left a comment. This was on flycheck/flycheck#1063