Note : This project is tested on Goerli testnet (instead of testing in Rinkeby as Rinkeby is going to depricate soon by Alchemy )
so for now,NFT is not displaying on testnets.opensea.io under goerli testnet.
Based on the OpenSea documentation testnets.opensea.io works only on the Rinkeby Blockchain.
.... in the coming days, Opensea will support Goerli testnet too
====>> so,This project will be useful in future.
==>> here the whitelisted addresses can mint Nfts in pre-sale.
==>> public sale will be opened only after 2 months.