I would suggest filing an issue with the plugin authors.
@henkk20670391 please see my recent thread Swift3 build error with cordova-plugin-qrscanner for some tips on how to get past this initial issue (switch to github sourced package should fix that)
This issue appears to be resolved with this but there is another build issue now. This time I think it is a phonegap build problem as build.phonegap is complaining about legacy swift version despite preference tags & code being swift 3.0 (I have build the library successfully in xcode latest under sierra so I know the library is good)
Are you using Phonegap Build or Phonegap CLI?
If you are using Phonegap Build I already answered on agranthnz thread, Phonegap Build doesn't run hooks and the plugin is using one for setting the Swift version. As the hook doesn't run, the plugin won't work.
If you are using Phonegap CLI, then provide more information, like CLI version