Update dependency markdown-it to v12.0.6

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
markdown-it	12.0.5 -> 12.0.6

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Release Notes

markdown-it/markdown-it

### [`v12.0.6`](https://togithub.com/markdown-it/markdown-it/blob/master/CHANGELOG.md#​1206---2021-04-16) [Compare Source](https://togithub.com/markdown-it/markdown-it/compare/12.0.5...12.0.6) ##### Fixed - Newline in `alt` should be rendered, [#​775](https://togithub.com/markdown-it/markdown-it/issues/775).

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Configuration

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