cmd/tailscale: rewrite --authkey to --auth-key

That way humans don't have to remember which is correct.

RELNOTE=--auth-key is the new --authkey, but --authkey still works

Updates tailscale/corp#3486

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

cmd/tailscale/tailscale.go

@@ -17,6 +17,7 @@ import (
 
 func main() {
 	args := os.Args[1:]
+	args = cli.CleanUpArgs(args)
 	if name, _ := os.Executable(); strings.HasSuffix(filepath.Base(name), ".cgi") {
 		args = []string{"web", "-cgi"}
 	}