Fix typo in object assign for replyOptions

Author: thejones

index.js

@@ -15,9 +15,10 @@ module.exports = async function (fastify, opts) {
   fromOpts.prefix = undefined
 
   const oldRewriteHeaders = (opts.replyOptions || {}).rewriteHeaders
-  const replyOpts = Object.assign({}, opts.replyOpts, {
+  const replyOpts = Object.assign({}, opts.replyOptions, {
     rewriteHeaders
   })
+
   fromOpts.rewriteHeaders = rewriteHeaders
 
   fastify.register(From, fromOpts)