Have dynamic check path

[jawakarD]

As of now, looks like the this action checks for the root path

wait-for-netlify-action/index.js

Line 32 in d85a22d

const url = `https://deploy-preview-${PR_NUMBER}--${siteName}.netlify.app`;

but some sites would not have the root path, but will have other pages. This will throw 404 when the action tries to access the non existing page and won't resolve to 200 at all.

Solution could be to accept a option check_path.

Would like to open a PR if it's fine.

[JakePartusch]

@jawakarD, sure go for it! I think that would be a fine enhancement.

Maybe it could be base_path which has a default of /?