feat: ansi 16 theme

[meowgorithm]

This revision adds a semi-secret theme that uses the 16 ANSI colors for people who like it when CLIs match their colorscheme. It can be enabled by setting SEQUIN_THEME to ansi, matchy, carlos or secret_carlos.

Under the hood, this themes uses the hot, new ANSI constants in Lip Gloss v2 Alpha.

[coveralls]

Pull Request Test Coverage Report for Build 11976924048

Details

• 80 of 109 (73.39%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-2.5%) to 87.883%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
main.go	19	23	82.61%
theme.go	61	86	70.93%

Totals
Change from base Build 11976306959:	-2.5%
Covered Lines:	660
Relevant Lines:	751

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💛 - Coveralls

[caarlos0]

need to move the //nolint:mnd to the new func, other than that lgtm