Add output slack message ID to update existing message

[Ciloe]

Hi there,

I saw that when you have github integration in you slack and work with pull request and actions test, we have only one message that change status when test are waiting/success/error.

With you package, I launch messages in slack when I deploy my project. But I have one message when it's running, and one more when it's finish (succeed or failed).

is it possible to have one message that change the status bar ?

Thanks !