Request: Add textbox to the actions field options

[royberris]

Hi,

I have a feature request for the action parameters. This is a single line textfield right now but it would be nice if we could have a textbox which supports multiple lines. I want to write a post action that adds a _headers file to the output for Netlify but right now I have to do this hardcoded because the input from the CMS does not support multiple lines.

I am using it so the rss index file returns with the right content type for browsers to understand.

Would like to contribute above action to the Netlify package because I think it will be useful. But of course above version is not enough for the package because it is static.