There seem to be some changes in .net core and Directory.GetCurrentDirectory() now doesn't return project path.
You need to pass your project path to the RunInDirectory
You can try something like this
var projectPath = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location.Substring(0, Assembly.GetEntryAssembly().Location.IndexOf("bin\\")));
var rs = new LocalReporting()
.RunInDirectory(Path.Combine(projectPath, "jsreport"))
...