tau: change default read_key to the correct one for the default worspace

bin/tau/taud/taud_config.toml

@@ -42,7 +42,7 @@
 #write_key = ""
 
 [workspace."darkfi-dev"]
-read_key = "2bCqQTd8BJgeUzH7JQELZxjQuWS8aCmXZ9C6w7ktNS1v"
+read_key = "4WhacatfZ314eM4aE2MYDUmDZczKpHwZo2u9zwQRaGhE"
 write_public_key = "Fgsc8tep4KX3Rb2drq8RxMyrHFWQ7wZaZPpF9F3GQYFG"
 # write_key = ""