Generates a signature for minting an asset on a given contract
Body
1stripe, shipstation, drip, twitter_bearer, epic_games, stardust, twitter_clientsecret, immutable_passport, sequence, google, walletConnect, auth0, privy, thirdweb, steam, discord, google_api, shopify, ultra, github 202
Use the id returned here to fetch the status and signature of the mint from the /api/minting/status/:id endpoint