Include OS label to flaky test

[RafaelGSS]

I believe it would be great to include the OS label to issues created as flaky test. It will save time for the person interested in fixing those issues in their OS.

I guess an acceptable approach would be:

1. Normalize the issue template (use checkbox to select the OS)
2. Automatically label issues based on step 1 (Not sure if we can adapt the other workflows such as label-pr)

What are your thoughts on this?

[targos]

Do you want to keep this open for 2. ?

[RafaelGSS]

Yes, I'll investigate how I can do that