Update minting contract to use `mustPayToPubKeyAddress`

[rynoV]

Currently (#22) there's a warning:

  in module Seabug.Contract.CnftMint
  at src/Seabug/Contract/CnftMint.purs:33:1 - 36:46 (line 33, column 1 - line 36, column 46)

    A custom warning occurred while solving type class constraints:

      Some wallets may not recognize addresses without a staking key component. Consider usingmustPayToPubKeyAddress

  in value declaration mintCnft

Don't think this is critical because the minting is working. It should be a quick fix, I just couldn't test it because Nami and Gero weren't working and my KeyWallet didn't have a staking key. The fix should be:

• Update CnftMint to use mustPayToPubKeyAddress instead of mustPayToPubKey (use ownerStake variable that's already defined)
• Update Mint to search for utxos at payPubKeyHashBaseAddress instead of payPubKeyHashEnterpriseAddress

[rynoV]

Update Mint to search for utxos at payPubKeyHashBaseAddress instead of payPubKeyHashEnterpriseAddress

Due to CTL's balancing, this isn't strictly necessary as the utxos get pulled in automatically, but I think it's best to be explicit about where we expect the CNFT to be.