Remove ruby versions 2.5.x
Remove ruby versions 2.5.x

Signed-off-by: Emily Johnson <9a47229397909c81b4d49bf5e885c401993e2588@vmware.com>

cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack