[Website] Social media link preview image looks bad in dark mode

The social media link preview image (a.k.a. social share image) for the Arrow site looks really really bad when displayed on Twitter with dark mode switched on:

I don't know whether this affects the preview image on other social media sites.

This is happening because the preview image is a transparent PNG image with black content on a transparent background, and the background becomes black in dark mode, leaving barely visible black on black.

I believe the preview image is controlled by these <meta> elements (depending on which social media site the preview is displayed on):

<meta property="og:image" content="https://arrow.apache.org/img/arrow.png">
<meta property="twitter:image" content="https://arrow.apache.org/img/arrow.png">

I think the simplest way to fix this would be to point these <meta> elements to a PNG image with an opaque white background.

Perhaps it's also possible to specify separate social share images for light and dark mode, but I'm not sure about that.