Lower to ruby 2.3

Author: lloeki

lib-injection/host_inject.rb

@@ -2,6 +2,6 @@
 # to call into the main one only for versions for which it is known-compatible
 # with at the language level.
 
-if RUBY_VERSION >= '2.5.'
+if RUBY_VERSION >= '2.3.'
   require File.expand_path(File.join(File.dirname(__FILE__), 'host_inject_main.rb'))
 end