cmd/utils: update Rinkeby deprecation message (#26496)

cmd/utils/flags.go

@@ -1899,9 +1899,9 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 		log.Warn("")
 		log.Warn("--------------------------------------------------------------------------------")
 		log.Warn("Please note, Rinkeby has been deprecated. It will still work for the time being,")
-		log.Warn("but there will be no further hard-forks shipped for it. Eventually the network")
-		log.Warn("will be permanently halted after the other networks transition through the merge")
-		log.Warn("and prove stable enough. For the most future proof testnet, choose Sepolia as")
+		log.Warn("but there will be no further hard-forks shipped for it.")
+		log.Warn("The network will be permanently halted in Q2/Q3 of 2023.")
+		log.Warn("For the most future proof testnet, choose Sepolia as")
 		log.Warn("your replacement environment (--sepolia instead of --rinkeby).")
 		log.Warn("--------------------------------------------------------------------------------")
 		log.Warn("")