Restrict dependent package versions required to versions supported by concerto

[sundhaug92]

passenger-d{ev,oc} 5.*
ruby < 2.4

[mfrederickson]

The concerto master branch should be able to handle ruby 2.4 and 2.5, and I've updated the control file here for ruby >= 2.3 to accommodate the requirements of the security patched gems. I'm not sure how to specify the passenger version like you want, since that's not listed in the dependencies (but libapache2-mod-passenger is...)