[Improvement] Add a github action to support merge cherry-picked PR automatically

[jerryshao]

What would you like to be improved?

Currently, each cherry-picked PR should be approved and merged manually. This is not convenient as most of the review/check are already done in the original PR. We should simply merge it automatically after the CI is passed.

How should we improve?

We should add a github action to merge the cherry-picked PR automatically.

[justinmclean]

Note this may not be allowed in ASF repos as only humans can commit

[mchades]

Is this still necessary?

[jerryshao]

It's not needed, I'm going to close it.