Use Buffer.from instead of deprecated new Buffer

lib/browser/rpc-server.js

@@ -148,7 +148,7 @@ const unwrapArgs = function (sender, args) {
       case 'array':
         return unwrapArgs(sender, meta.value)
       case 'buffer':
-        return new Buffer(meta.value)
+        return Buffer.from(meta.value)
       case 'date':
         return new Date(meta.value)
       case 'promise':