key.rb in cose-0.9.0

- old
+ new

@@ -1,4 +1,6 @@
+# frozen_string_literal: true
+
 require "cbor"
 require "cose/key/ec2"
 require "cose/key/okp"
 require "cose/key/rsa"
 require "cose/key/symmetric"