fix unit install line

README.md

@@ -7,7 +7,7 @@ cd he-ddns
 sudo install -o root -g root -m 0755 he-ddns /usr/local/bin/
 sudo install -o root -g root -m 0644 he-ddnsrc /usr/local/etc/
 sudoedit /usr/local/etc/he-ddnsrc
-sudo install -o root -g root -m 0644 he-ddns?@.{service,timer} /etc/systemd/system
+sudo install -o root -g root -m 0644 he-ddns.{service,timer} /etc/systemd/system/
 sudo systemctl daemon-reload
 sudo systemctl enable --now he-ddns.timer
 ```