Hardhat Verify API key names

hardhatEtherscan.js

module.exports = {
  networks: {
    mainnet: { ... },
    testnet: { ... }
  },
  etherscan: {
    apiKey: {
        mainnet: "YOUR_ETHERSCAN_API_KEY",
        ropsten: "YOUR_ETHERSCAN_API_KEY",
        rinkeby: "YOUR_ETHERSCAN_API_KEY",
        goerli: "YOUR_ETHERSCAN_API_KEY",
        kovan: "YOUR_ETHERSCAN_API_KEY",
        // binance smart chain
        bsc: "YOUR_BSCSCAN_API_KEY",
        bscTestnet: "YOUR_BSCSCAN_API_KEY",
        // huobi eco chain
        heco: "YOUR_HECOINFO_API_KEY",
        hecoTestnet: "YOUR_HECOINFO_API_KEY",
        // fantom mainnet
        opera: "YOUR_FTMSCAN_API_KEY",
        ftmTestnet: "YOUR_FTMSCAN_API_KEY",
        // optimism
        optimisticEthereum: "YOUR_OPTIMISTIC_ETHERSCAN_API_KEY",
        optimisticKovan: "YOUR_OPTIMISTIC_ETHERSCAN_API_KEY",
        // polygon
        polygon: "YOUR_POLYGONSCAN_API_KEY",
        polygonMumbai: "YOUR_POLYGONSCAN_API_KEY",
        // arbitrum
        arbitrumOne: "YOUR_ARBISCAN_API_KEY",
        arbitrumTestnet: "YOUR_ARBISCAN_API_KEY",
        // avalanche
        avalanche: "YOUR_SNOWTRACE_API_KEY",
        avalancheFujiTestnet: "YOUR_SNOWTRACE_API_KEY",
        // moonbeam
        moonbeam: "YOUR_MOONBEAM_MOONSCAN_API_KEY",
        moonriver: "YOUR_MOONRIVER_MOONSCAN_API_KEY",
        moonbaseAlpha: "YOUR_MOONBEAM_MOONSCAN_API_KEY",
        // harmony
        harmony: "YOUR_HARMONY_API_KEY",
        harmonyTest: "YOUR_HARMONY_API_KEY",
        // xdai and sokol don't need an API key, but you still need
        // to specify one; any string placeholder will work
        xdai: "api-key",
        sokol: "api-key",
        aurora: "api-key",
        auroraTestnet: "api-key",
    }
  }
};