Add dependency on ostruct

Ruby 3.4 moves OpenStruct to a bundled gem Ruby 3.5 will raise errors

e.g. rails/rails#51468

Author: errm

lib/streamy/event_handler.rb

@@ -1,4 +1,5 @@
 require "active_support/core_ext/hash/indifferent_access"
+require "ostruct"
 
 module Streamy
   class EventHandler

streamy.gemspec

@@ -45,4 +45,5 @@ Gem::Specification.new do |spec| # rubocop:disable Metrics/BlockLength
   spec.add_dependency "avro_turf", "~> 1.3.0"
   spec.add_dependency "waterdrop", ">= 2.4.10", "< 3.0.0"
   spec.add_dependency "webmock", "~> 3.3"
+  spec.add_dependency "ostruct"
 end

test/avro_deserializer_test.rb

@@ -1,6 +1,7 @@
 require "test_helper"
 require "avro_turf/test/fake_confluent_schema_registry_server"
 require "webmock/minitest"
+require "ostruct"
 
 module Streamy
   class AvroDeserializerTest < Minitest::Test