chore: add image to pubspec.yaml

[josxha]

This pr is a proposal to add the fm logo as image to the pubspec.yaml file.

The result would look similar to here and further improve the package visibility on pub.dev:

The image resolution is currently in this pr only 200x200px as this was the biggest that I could find.

[JaffaKetchup]

LGTM!

I unfortunately lost the original design files and high quality export. Might need to change it at some point soon anyway, but don't really have any ideas.

Also just be aware that this is not recommended practise, but I'm fine with it:

Don't include logos or other branding imagery in this section.

[josxha]

Also just be aware that this is not recommended practise, but I'm fine with it.

Yep, red that too but tbh I think the logo fits better than some ordinary screenshot. 😄

Do you have an idea why the pana score fails?

0/10 points: Package has an example and has no issues with screenshots\n\nFound 4 issues. Showing the first 2:\n\n* /tmp/pana_TLPLCL/./images/logo.webp: Tried interpreting screenshot as WebP with webpinfo \"/tmp/pana_TLPLCL/./images/logo.webp\" failed with exit code 2.\n* /tmp/pana_TLPLCL/./images/logo.webp: Converting screenshot with cwebp \"/tmp/pana_TLPLCL/./images/logo.webp\" -o \"/tmp/ICOKKH/gen/logo.webp\" failed with exit code 2.

[JaffaKetchup]

"summary": "### [] 0/10 points: Package has an example and has no issues with screenshots\n\nFound 4 issues. Showing the first 2:\n\n /tmp/pana_TLPLCL/./images/logo.webp: Tried interpreting screenshot as WebP with webpinfo \"/tmp/pana_TLPLCL/./images/logo.webp\" failed with exit code 2.\n* /tmp/pana_TLPLCL/./images/logo.webp: Converting screenshot with cwebp \"/tmp/pana_TLPLCL/./images/logo.webp\" -o \"/tmp/ICOKKH/gen/logo.webp\" failed with exit code 2."

Not sure what to make from that.

[josxha]

Closing this pr, because of the valid concerns with the current fleaflet logo. Need to revisit once we have one.