add ruby 3.0 support

[kbrock]

made the kwargs fixes.

added ruby 3.0 to the matrix.

Fixes #70

[jrafanie]

LGTM, this code is explicitly passing a merged hash so the test should know to do this explicitly in light of 3.0

manageiq-messaging/lib/manageiq/messaging/kafka/client.rb

Lines 83 to 95 in 4fbccac

	@kafka_client = ::Rdkafka::Config.new(rdkafka_connection_opts(options))
	end
	def rdkafka_connection_opts(options)
	hosts = Array(options[:hosts] || options[:host])
	hosts.collect! { |host| "#{host}:#{options[:port]}" }
	result = {:"bootstrap.servers" => hosts.join(',')}
	result[:"client.id"] = options[:client_ref] if options[:client_ref]
	result[:"sasl.username"] = options[:username] if options[:username]
	result[:"sasl.password"] = options[:password] if options[:password]
	result.merge(options.except(:port, :host, :hosts, :encoding, :protocol, :client_ref, :username, :password))