Fix WooCommerce API path

src/WooCommerce.hs

@@ -60,7 +60,7 @@ payWooOrder ::
   -> BS.ByteString -- Total ZEC for order
   -> IO ()
 payWooOrder u i o t p z = do
-  wooReq <- parseRequest $ u ++ "wc-api/zpmtcallback"
+  wooReq <- parseRequest $ u ++ "/wc-api/zpmtcallback"
   let req =
         setRequestQueryString
           [ ("token", Just t)