Why I can not target iOS 13.3 on the xcode latest vetsion
Why I can not target iOS 13.3 on the latest xcode version
Because Xcode 11.3.1 only has the iOS 13.2 SDK, not 13.3. It's not clear if that was an oversight, or if there weren't any SDK changes in 13.3.
So, just set your deployment target to 13.2, and you should be good to go.