Support execute local script over ssh

[appleboy]

ref: appleboy/ssh-action#186

[kyle-leonhard]

@appleboy, I'm interested in seeing appleboy/ssh-action#186 happen. Can I contribute a PR to drone-ssh?

Is it as easy as adding a new script.file flag that's read in main.go and appended to the scripts?

Something like (#285):

if f := c.String("script.file"); f != "" {
	s, err := os.ReadFile(f)
	if err != nil {
		return err
	}
	scripts = append(scripts, string(s))
}

[appleboy]

@kyle-leonhard Yes. you can do it. Thanks. If you don't have time, I plan to write a version today for validation testing.

[kyle-leonhard]

Sweet! Before I saw your message, I started plumbing it in ssh-action: https://github.com/appleboy/ssh-action/pull/341/files. Happy to contribute that or not