README: logos render in a broken manner

[isaac-io]

After the merge of #135, rendering of the repo page and the readme page is broken on mobile (horizontal scrolling is activated and the logo is partially hidden) due to the heading logo having a fixed width, instead of a relative width with a max-width:

Additionally, on desktop with dark mode the logos look bad, and the bee is almost invisible:

[rtpro]

@isaac-io

1. Image Size - I've tested the image size issue, and it looks okay on Pixel 6.

What device and browser are you using?

2. Dark Mode - I'm checking what can be done with the images to look better with Dark mode.

[isaac-io]

What device and browser are you using?

My screenshot was from Firefox Mobile on a Motorola device, but it seems to render fine now. There seems to have been a change on GitHub's side in the mean time (the image now has style="max-width: 100%; display: inline-block;" applied to it), so you can disregard that issue.

[rtpro]

Update: awaiting shiny new graphics compatible with Dark Mode.