Here is a start, they added a client_secret token to auth so I defined a client_secret variable and change some code in get oauth token to include that in the post data
postdata = {'grant_type': 'password',
'username': workflow.get_variable('username'),
'password' : workflow.get_variable('password'),
'client_id' : 'ghost-admin',
'client_secret' : workflow.get_variable('client_secret')}
I think I used chrome developer tools to see the client secret when I logged in on a web browser and then set the variable with that. I don't have a computer handy to check for you.
I can't remember if that is all I did so let me know if that doesn't work. If that does I'll find the code I changed to get tags coming back as well.