Account for missing response fields in Zebra response (#43)

This PR adds code to account for the missing `time` field in the Zebra response for blocks and raw transactions.

Reviewed-on: #43
Co-authored-by: pitmutt <rene@vergara.network>
Co-committed-by: pitmutt <rene@vergara.network>

src/ZcashHaskell/Types.hs

@@ -7,7 +7,7 @@
 -- Copyright   :  2022-2024 Vergara Technologies
 -- License     :  MIT
 --
--- Maintainer  :  pitmut@vergara.tech
+-- Maintainer  :  pitmutt@vergara.tech
 -- Stability   :  experimental
 -- Portability :  unknown
 --
@@ -31,6 +31,7 @@ import qualified Data.ByteString as BS
 import qualified Data.ByteString.Char8 as C
 import Data.HexString
 import Data.Int
+import Data.Maybe (fromMaybe)
 import Data.Structured
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as E
@@ -199,9 +200,9 @@ instance FromJSON BlockResponse where
     withObject "BlockResponse" $ \obj -> do
       c <- obj .: "confirmations"
       h <- obj .: "height"
-      t <- obj .: "time"
+      t <- obj .:? "time"
       txs <- obj .: "tx"
-      pure $ BlockResponse c h t txs
+      pure $ BlockResponse c h (fromMaybe 0 t) txs
 
 -- | Type to represent response from the `zcashd` RPC `getrawtransaction`
 data RawTxResponse = RawTxResponse