Move Ruby version requirement above dependencies

Author: ashmaroli

jekyll-watch.gemspec

@@ -17,9 +17,9 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r!^bin/!) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
+  spec.required_ruby_version = ">= 2.3.0"
 
   spec.add_runtime_dependency "listen", "~> 3.0"
-  spec.required_ruby_version = ">= 2.3.0"
 
   require "rbconfig"
   if RbConfig::CONFIG["host_os"] =~ %r!mswin|mingw|cygwin!