[PATCH] Properly override respond_to? in Raindrops::Middleware::Proxy

[Dmytro Shteflyuk <kpumuk@kpumuk.info>]

Correct method definition according to Ruby documentation (https://ruby-doc.org/core-2.4.1/Object.html#method-i-respond_to-3F) is:

    respond_to?(string, include_all=false) → true or false

Rack started using second argument starting from version 2:

https://github.com/rack/rack/blob/master/lib/rack/body_proxy.rb#L14

If raindrops is used in Rack 2+ applications, an exception is raised:

    ArgumentError: wrong number of arguments (2 for 1)
        <ROOT>/gems/raindrops-0.18.0/lib/raindrops/middleware/proxy.rb:30:in `respond_to?'
        <ROOT>/gems/rack-2.0.3/lib/rack/body_proxy.rb:14:in `respond_to?'
---
 lib/raindrops/middleware/proxy.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/raindrops/middleware/proxy.rb b/lib/raindrops/middleware/proxy.rb
index 1cf437c..a7c8e66 100644
--- a/lib/raindrops/middleware/proxy.rb
+++ b/lib/raindrops/middleware/proxy.rb
@@ -27,9 +27,9 @@ def to_path
 
   # Rack servers use +respond_to?+ to check for the presence of +close+
   # and +to_path+ methods.
-  def respond_to?(m)
+  def respond_to?(m, include_all = false)
     m = m.to_sym
-    :close == m || @body.respond_to?(m)
+    :close == m || @body.respond_to?(m, include_all)
   end
 
   # Avoid breaking users of non-standard extensions (e.g. #body)
-- 
2.13.2