Run CI against Ruby 3.2 (#742)

* Fix ruby 3.2 spec
* Run CI on ruby 3.2

Author: koheisg

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        ruby: [ ruby-2.6, ruby-2.7, ruby-3.0, ruby-3.1 ]
+        ruby: [ ruby-2.6, ruby-2.7, ruby-3.0, ruby-3.1, ruby-3.2 ]
         os: [ ubuntu-latest ]
 
     steps:

spec/lib/http/options/headers_spec.rb

@@ -14,7 +14,11 @@
   end
 
   it "accepts any object that respond to :to_hash" do
-    x = Struct.new(:to_hash).new("accept" => "json")
+    x = if RUBY_VERSION >= "3.2.0"
+          Data.define(:to_hash).new(:to_hash => { "accept" => "json" })
+        else
+          Struct.new(:to_hash).new({ "accept" => "json" })
+        end
     expect(opts.with_headers(x).headers["accept"]).to eq("json")
   end
 end