Fix README

Author: ericof

README.md

@@ -35,7 +35,7 @@ GitHub Action and Docker image used to deploy a Docker stack on a Docker Swarm.
 | `deploy_timeout` | `DEPLOY_TIMEOUT` | Seconds, to wait until the deploy finishes | | **600** |
 | `stack_file` | `STACK_FILE` | Path to the stack file used in the deploy. | ✅ | |
 | `stack_name` | `STACK_NAME` | Name of the stack to be deployed. | ✅ | |
-| `stack_paran` | `STACK_PARAM` | Additional parameter (env var) to be passed to the stack. | | |
+| `stack_param` | `STACK_PARAM` | Additional parameter (env var) to be passed to the stack. | | |
 | `debug` | `DEBUG` | Verbose logging | | **0** |