feat: add kebab-case options to cli flags

[khendrikse]

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Summary

Fixes https://github.com/netlify/team-dev/issues/55

This is an example of the way we could work on implementing new kebab-case options as CLI flags, as described in the above ticket.

In this example you can see how we could achieve the following:

• Add kebab-case options to flags that are currently camelCase.
• Keep supporting camelCase, but hide the option from the help command.

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[github-actions]

📊 Benchmark results

Comparing with 87adddc

Package size: 267 MB

(no change)

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└───┴──┴────┴──┴────┴──┴────┴──┴────┴──┴──>
    T-4     T-3     T-2     T-1      T    

Legend

• T-4 (bce1f2c): 260 MB
• T-3 (2d3923c): 260 MB
• T-2 (6726bf4): 267 MB
• T-1 (87adddc): 267 MB
• T (current commit): 267 MB

[khendrikse]

@eduardoboucas mentioned that it might be worth not deprecating the old options and just keeping them but hidden. This way we don't have to add all the deprecation logic and it should not be a big maintenance overhead.

Planning to reduce the scope of the issue to not include warnings about deprecating older options.

[eduardoboucas]

❤️ Nice! Left a couple of minor comments, but this is looking great.