Use pull_request.user, not actor to determine PR user (#15504)
Use pull_request.user, not actor to determine PR user (#15504)

In most cases these are the same -- the one exception is when
(re)opening an issue, in which case the actor is going to be someone
with commit rights to a repo, and we don't want the mere act of
re-opening to cause a PR to run on self-hosted infrastructure as that
would be surprising (and potentially unsafe)
bolkedebruin/airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,apache/airflow,dhuang/incubator-airflow,mistercrunch/airflow,nathanielvarona/airflow,apache/airflow,dhuang/incubator-airflow,nathanielvarona/airflow,dhuang/incubator-airflow,apache/incubator-airflow,nathanielvarona/airflow,nathanielvarona/airflow,cfei18/incubator-airflow,apache/incubator-airflow,cfei18/incubator-airflow,mistercrunch/airflow,danielvdende/incubator-airflow,bolkedebruin/airflow,nathanielvarona/airflow,dhuang/incubator-airflow,apache/airflow,apache/airflow,bolkedebruin/airflow,sekikn/incubator-airflow,bolkedebruin/airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,lyft/incubator-airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,Acehaidrey/incubator-airflow,sekikn/incubator-airflow,mistercrunch/airflow,apache/airflow,sekikn/incubator-airflow,danielvdende/incubator-airflow,danielvdende/incubator-airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,apache/airflow,bolkedebruin/airflow,apache/incubator-airflow,sekikn/incubator-airflow,cfei18/incubator-airflow,lyft/incubator-airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,mistercrunch/airflow