Logos in README.rst are hard to read in Dark Mode

[spenserblack]

Just stumbled on this project a few seconds ago. Looks really cool!

While going through the readme, I noticed that it was pretty hard to read some of the logos under "DjangoQL is used by:" in GitHub with dark mode. The text for Red Hat and teamplify, for example, is nearly invisible. Not sure how readable you want the readme to be on GitHub (maybe you'd prefer users read it on PyPI?), but here are some docs to help render images for light and dark themes. Though I'm personally not a fan of putting HTML in readmes 😅