ruby-xz requires Ruby version >= 2.3.0

[decaz]

The newer version of ruby-xz was released (https://github.com/Quintus/ruby-xz/blob/master/HISTORY.rdoc#100-2018-05-20) therefore fpm cannot be installed:

$ gem install --no-ri --no-rdoc fpm
Successfully installed cabin-0.9.0                                                                                                                                                                                                                                             
Successfully installed backports-3.11.3                                                                                                                                                                                                                                        
Successfully installed arr-pm-0.0.10                                                                                                                                                                                                                                           
Successfully installed clamp-1.0.1                                                                                                                                                                                                                                             
Building native extensions.  This could take a while...                                                                                                                                                                                                                        
ERROR:  Error installing fpm:                                                                                                                                                                                                                                                  
        ruby-xz requires Ruby version >= 2.3.0.                                                                                                                                                                                                                                
...

I guess ruby-xz==0.2.3 should be specified within dependencies.