flink-operator-1.5.0 supports which versions of Kubernetes

[吴圣运]

Hi,

I'm using flink-operator-1.5.0 and I need to deploy it to Kubernetes 1.20. I 
want to confirm if this version of flink-operator is compatible with Kubernetes 
1.20. I cannot find the compatible matrix in the github page. Could you help me 
confirm?

Thanks 
shengyun.wu