feat: add icon for commitizen

[juliolmuller]

Description

Add icon for commitizen configuration files.

Clsoes #2016

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[lucas-labs]

Thanks for fixing the margins!

I will add some changes to improve pixel perfectness later today.

[lucas-labs]

I removed the "cz" inside the logo, because it was too small to be able to see it at 16px.
Also aligned the internal lines to the 16x16 grid to make it look sharper at that size.

[PKief]

@lucas-labs thank you for the adjustments. It looks nice now!

[github-actions]

Merge Successful

Thanks for your contribution! 🎉

The changes will be part of the upcoming update on the Marketplace.