Limits CodeQL workflow to run only in the Apache Airflow repo (#11264)
Limits CodeQL workflow to run only in the Apache Airflow repo (#11264)

It has been raised quite a few times that workflow added in forked
repositories might be pretty invasive for the forks - especially
when it comes to scheduled workflows as they might eat quota
or at least jobs for those organisations/people who fork
repositories.

This is not strictly necessary because Recently GitHub recognized this as being
a problem and introduced new rules for scheduled workflows. But for people who
are already forked, it would be nice to not run those actions. It is enough
that the CodeQL check is done when PR is opened to the "apache/airflow"
repository.

Quote from the emails received by Github (no public URL explaining it yet):

> Scheduled workflows will be disabled by default in forks of public repos and in
public repos with no activity for 60 consecutive days.  We’re making two
changes to the usage policy for GitHub Actions. These changes will enable
GitHub Actions to scale with the incredible adoption we’ve seen from the GitHub
community. Here’s a quick overview:

> * Starting today, scheduled workflows will be disabled by default in new forks of
public repositories.
> * Scheduled workflows will be disabled in public repos with
no activity for 60 consecutive days.
mrkm4ntr/incubator-airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,mrkm4ntr/incubator-airflow,nathanielvarona/airflow,bolkedebruin/airflow,airbnb/airflow,sekikn/incubator-airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,cfei18/incubator-airflow,sekikn/incubator-airflow,mistercrunch/airflow,Acehaidrey/incubator-airflow,lyft/incubator-airflow,apache/airflow,airbnb/airflow,nathanielvarona/airflow,dhuang/incubator-airflow,apache/incubator-airflow,bolkedebruin/airflow,apache/airflow,DinoCow/airflow,apache/airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,mistercrunch/airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow,mistercrunch/airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,bolkedebruin/airflow,nathanielvarona/airflow,airbnb/airflow,mrkm4ntr/incubator-airflow,bolkedebruin/airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,dhuang/incubator-airflow,sekikn/incubator-airflow,DinoCow/airflow,apache/airflow,DinoCow/airflow,apache/incubator-airflow,dhuang/incubator-airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,lyft/incubator-airflow,lyft/incubator-airflow,mistercrunch/airflow,apache/airflow,mrkm4ntr/incubator-airflow,apache/airflow,danielvdende/incubator-airflow,sekikn/incubator-airflow,nathanielvarona/airflow,airbnb/airflow,bolkedebruin/airflow,DinoCow/airflow,nathanielvarona/airflow,cfei18/incubator-airflow