Upgrade the irb command to use irb:debug integration

This means that user will get an IRB session that has access to the debug
commands too by activating IRB's debug integration automatically:
https://github.com/ruby/irb#debugging-with-irb

debug.gemspec

@@ -27,6 +27,6 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
   spec.extensions    = ['ext/debug/extconf.rb']
 
-  spec.add_dependency "irb", ">= 1.5.0" # for binding.irb(show_code: false)
-  spec.add_dependency "reline", ">= 0.3.1"
+  spec.add_dependency "irb", "~> 1.8.0" # for irb:debug integration
+  spec.add_dependency "reline", ">= 0.3.8"
 end

lib/debug/thread_client.rb

@@ -1038,13 +1038,14 @@ def wait_next_action_
           when :call
             result = frame_eval(eval_src)
           when :irb
-            require 'irb' # prelude's binding.irb doesn't have show_code option
-            begin
-              result = frame_eval('binding.irb(show_code: false)', binding_location: true)
-            ensure
-              # workaround: https://github.com/ruby/debug/issues/308
-              Reline.prompt_proc = nil if defined? Reline
-            end
+            require "irb"
+            IRB.setup(location, argv: [])
+            workspace = IRB::WorkSpace.new(current_frame&.binding || TOPLEVEL_BINDING)
+            irb = IRB::Irb.new(workspace)
+            IRB.conf[:MAIN_CONTEXT] = irb.context
+            IRB::Debug.send(:configure_irb_for_debugger, irb)
+            SESSION.reset_ui(IRB::Debug::UI.new(thread, irb))
+            IRB::Debug.setup(irb)
           when :display, :try_display
             failed_results = []
             eval_src.each_with_index{|src, i|