a11y - improve color contrast on the homepage

Describe the bug Low color contrast on the (dark mode) homepage in several places which makes it difficult to read the information,
To Reproduce Steps to reproduce the behavior:

1. Go to https://testing-library.com/ (with dark mode enableD)
2. Scroll down to 'Who is Using This?, Libbraries, Awards
3. See low contrast on some of the icons and text

Expected behavior Expect to see higher level of contrast for AutoDesk, Facebook Open Source, Walmart Labs, React Native (logo) etc. and "The Most Impactful Contribution to the Community" under Open Source Awards.
Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS] - MacOS
• Browser [e.g. chrome, safari] - Chrome and Safari

Additional context

This could be resolved by using the <picture> element with a srcset and changing the image file based on a users current color scheme as outlined in this article: https://larsmagnus.co/blog/how-to-make-images-react-to-light-and-dark-mode

Open https://testing-library.com/ in dark mode and inspect the homepage sections named in the report: Who is Using This?, Libraries, Awards, and Open Source Awards. Identify the assets or styles controlling the listed logos, icons, and text, then verify improved contrast in Chrome and Safari for the reported content.