Update support policy for Python and Kubernetes (#15612)
Update support policy for Python and Kubernetes (#15612)

Following discussion here:

https://lists.apache.org/thread.html/r04f228319206ab920088c89f1001482671ca06b3b6b5cc12477c76ab%40%3Cdev.airflow.apache.org%3E

we update the policy of supporting Python/K8S versions.
lyft/incubator-airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,danielvdende/incubator-airflow,cfei18/incubator-airflow,dhuang/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow,mistercrunch/airflow,apache/airflow,apache/incubator-airflow,nathanielvarona/airflow,bolkedebruin/airflow,sekikn/incubator-airflow,mistercrunch/airflow,Acehaidrey/incubator-airflow,bolkedebruin/airflow,lyft/incubator-airflow,danielvdende/incubator-airflow,apache/incubator-airflow,lyft/incubator-airflow,apache/airflow,apache/airflow,Acehaidrey/incubator-airflow,apache/airflow,Acehaidrey/incubator-airflow,mistercrunch/airflow,Acehaidrey/incubator-airflow,cfei18/incubator-airflow,apache/incubator-airflow,apache/incubator-airflow,Acehaidrey/incubator-airflow,dhuang/incubator-airflow,bolkedebruin/airflow,nathanielvarona/airflow,danielvdende/incubator-airflow,dhuang/incubator-airflow,sekikn/incubator-airflow,sekikn/incubator-airflow,dhuang/incubator-airflow,nathanielvarona/airflow,mistercrunch/airflow,apache/airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,apache/airflow,cfei18/incubator-airflow,bolkedebruin/airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,bolkedebruin/airflow,Acehaidrey/incubator-airflow,sekikn/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow