cmd, internal: update copyright year to 2023 (#26382)

* internal/flags: update copyright year to 2023

* cmd/geth: update copyright year to 2023

cmd/geth/main.go

@@ -206,7 +206,7 @@ func init() {
 	// Initialize the CLI app and start Geth
 	app.Action = geth
 	app.HideVersion = true // we have a command to print the version
-	app.Copyright = "Copyright 2013-2022 The go-ethereum Authors"
+	app.Copyright = "Copyright 2013-2023 The go-ethereum Authors"
 	app.Commands = []*cli.Command{
 		// See chaincmd.go:
 		initCommand,