Feature Request: Update the centering when opening a new `:Startify`

Would it be possible to implement a way to re-render the header when opening Startify in a new window?
Maybe a function `startify#update()` who knows.... I'm just looking for a way to recenter it.

For example, open nvim in fullscreen, then do a vsplit.. This is the result:


Reproduce the reported flow by opening nvim in fullscreen, launching Startify, and then creating a vsplit. Inspect the Startify rendering and centering entry points; done means the header recenters or can be re-rendered correctly when the window size changes.

Written by the indexing model from the issue text.