Updated operator-sdk doc link (#2257)
Updated operator-sdk doc link (#2257)

Under section Add your Operator,  `you are new to Kubernetes Operators start [here]` is redirecting to repo `https://github.com/operator-framework/getting-started` which is out of date(https://github.com/operator-framework/getting-started/issues/80#issuecomment-682670011). So updated with operator sdk doc `https://sdk.operatorframework.io/`

Signed-off-by: Tanveer Alam <81e9bfead555818c8e5df0800c238f11821807b7@gmail.com>
operator-framework/community-operators,operator-framework/community-operators,operator-framework/community-operators