Update dependency mjml to v4.12.0

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
mjml (source)	4.11.0 -> 4.12.0

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Release Notes

mjmlio/mjml

### [`v4.12.0`](https://togithub.com/mjmlio/mjml/releases/v4.12.0) [Compare Source](https://togithub.com/mjmlio/mjml/compare/v4.11.0...v4.12.0) #### Features - allow to add text before doctype ([#​2146](https://togithub.com/mjmlio/mjml/issues/2146)) - allow to use a .mjmlconfig.js, allow to provide preprocessors in mjmlconfig.js ([#​2249](https://togithub.com/mjmlio/mjml/issues/2249)) - expose mjml file path in components props ([#​2344](https://togithub.com/mjmlio/mjml/issues/2344)) #### Fixes - watch on non mjml includes ([#​2261](https://togithub.com/mjmlio/mjml/issues/2261)) - better error message when malformed mjml ([#​2372](https://togithub.com/mjmlio/mjml/issues/2372))

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