Update pry dev dependency

This fixes the error `cannot load such file -- ostruct`

Author: alexgenco

neovim.gemspec

@@ -24,7 +24,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "logger"
 
   spec.add_development_dependency "bundler"
-  spec.add_development_dependency "pry", "~> 0.14"
+  spec.add_development_dependency "pry", "~> 0.15"
   spec.add_development_dependency "pry-byebug"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "rspec"