cmd/tailscale/cli: remove Beta tag from tailscale update (#11529)

Updates #cleanup

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>

cmd/tailscale/cli/update.go

@@ -20,7 +20,7 @@ import (
 var updateCmd = &ffcli.Command{
 	Name:       "update",
 	ShortUsage: "update",
-	ShortHelp:  "[BETA] Update Tailscale to the latest/different version",
+	ShortHelp:  "Update Tailscale to the latest/different version",
 	Exec:       runUpdate,
 	FlagSet: (func() *flag.FlagSet {
 		fs := newFlagSet("update")