feat: #8292 (QBadge) add round prop

[suyundukov]

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Documentation
• Code style update
• Refactor
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Does this PR introduce a breaking change? (check one)

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• No

The PR fulfills these requirements:

• It's submitted to the dev branch and not the master branch
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• It's been tested on a Cordova (iOS, Android) app
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[pdanpdan]

#8292

[rstoenescu]

Thanks for contributing!
Changed the "round" to "rounded" to match the syntax with other components as QBadge with this prop is not perfectly circle.

[rstoenescu]

Nice work. A well done PR. Contains docs, examples, API.
I especially like the "1em" change which sealed the deal to merge it :)
Will be available in Quasar v1.15.2.