Update erc-5521.md

ERCS/erc-5521.md

@@ -5,7 +5,7 @@ description: An ERC-721 extension to construct reference relationships among NFT
 author: Saber Yu (@OniReimu), Qin Wang <qin.wang@data61.csiro.au>, Shange Fu <shange.fu@monash.edu>, Yilin Sai <yilin.sai@data61.csiro.au>, Shiping Chen <shiping.chen@data61.csiro.au>, Sherry Xu <xiwei.xu@data61.csiro.au>, Jiangshan Yu <jiangshan.yu@monash.edu>
 discussions-to: https://ethereum-magicians.org/t/eip-x-erc-721-referable-nft/10310
 status: Last Call
-last-call-deadline: 2024-04-30
+last-call-deadline: 2024-06-07
 type: Standards Track
 category: ERC
 created: 2022-08-10