Improve CI triggers

[simPod]

• do not run on push expect when branch is master to prevent double runs in PRs
• run CI automatically daily

[mfn]

drop workflow_dispatch as it has no effect here (?)

IMHO that's not true: it just means a user with appropriate permission has the button to run the workflow: otherwise this button isn't available. That's useful to quickly re-run it as a maintainer.

[simPod]

@mfn can you point me to what button do you mean? I have this available without need for workflow_dispatch

[enumag]

@simPod It's for this. It appears in the Actions panel if you have workflow_dispatch and the necessary privileges.

[simPod]

Thanks, I've adapted the PR