fix: image name in action (#7)

Author: MatiasG19

action.yml

@@ -14,6 +14,6 @@ inputs:
     required: true
 runs:
   using: "docker"
-  image: "ghcr.io/matiasg19/ping:latest"
+  image: "docker://ghcr.io/matiasg19/ping:latest"
   args: ["${{ inputs.url }}", "${{ inputs.attempts }}"]
   entrypoint: "/ping.sh"