fix

Author: tomaszduda23

content/components/ota/zephyr_mcumgr.md

@@ -58,7 +58,7 @@ esphome upload h.yaml --device 00:11:22:33:44:55
 To connect and update the device over serial:
 
 ```bash
-esphome upload h.yaml --device /dev/ttyACM0
+esphome upload h.yaml
 ```
 
 Or connect to a specific serial: