[README] Badges to pub.dev scores

[bruno-garcia]

Description

Proposed badges based on pub.dev scores.
I've added a couple to show the idea. If this PR would be welcomed, I'd gladly add all of them.

Removed the draft tag to get some feedback. Would still add all the other badges if it's a go.

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]). This will ensure a smooth and quick review process.

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• My PR includes unit or integration tests for all changed/updated/fixed behaviors (See [Contributor Guide]).
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (flutter analyze) does not report any problems on my PR.
• I read and followed the [Flutter Style Guide].
• The title of the PR starts with the name of the plugin surrounded by square brackets, e.g. [shared_preferences]
• I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy].
• I updated CHANGELOG.md to add a description of the change.
• I signed the [CLA].
• I am willing to follow-up on review comments in a timely manner.

[bruno-garcia]

I was hoping to re-trigger CI since doesn't seem this change is causing the breakage.

[mit-mit]

Hi @bruno-garcia what a great idea for a badging tool! However, I think we need to find a resolution to bruno-garcia/badges.bar#2 before we merge this.

[bruno-garcia]

That makes sense. I'll close this PR for now to avoid the noise.
I'll raise a new one once the badges are rendered based on a proper API call.

Thanks @mit-mit