Simplify release process for PyPI snapshots (#13020)
Simplify release process for PyPI snapshots (#13020)

Setuptools has a built in mechanism for adding a `suffix` to a version,
so we don't have to edit a file and then remember to delete it!

It's a little bit messy to get the suffix like this -- using sed to
strip out any leading digits or periods, but it's copy-pasteable this
way.
dhuang/incubator-airflow,bolkedebruin/airflow,airbnb/airflow,airbnb/airflow,mistercrunch/airflow,danielvdende/incubator-airflow,apache/airflow,lyft/incubator-airflow,lyft/incubator-airflow,nathanielvarona/airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,apache/incubator-airflow,bolkedebruin/airflow,sekikn/incubator-airflow,bolkedebruin/airflow,cfei18/incubator-airflow,bolkedebruin/airflow,nathanielvarona/airflow,mistercrunch/airflow,DinoCow/airflow,Acehaidrey/incubator-airflow,nathanielvarona/airflow,dhuang/incubator-airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,apache/airflow,Acehaidrey/incubator-airflow,mistercrunch/airflow,cfei18/incubator-airflow,lyft/incubator-airflow,airbnb/airflow,sekikn/incubator-airflow,dhuang/incubator-airflow,lyft/incubator-airflow,apache/airflow,DinoCow/airflow,apache/incubator-airflow,dhuang/incubator-airflow,apache/incubator-airflow,nathanielvarona/airflow,airbnb/airflow,DinoCow/airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,apache/airflow,apache/airflow,apache/airflow,cfei18/incubator-airflow,sekikn/incubator-airflow,apache/incubator-airflow,DinoCow/airflow,cfei18/incubator-airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,sekikn/incubator-airflow,danielvdende/incubator-airflow,danielvdende/incubator-airflow,bolkedebruin/airflow,mistercrunch/airflow,nathanielvarona/airflow,danielvdende/incubator-airflow