Bump autoprefixer to 10.4.20

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
autoprefixer	10.4.19 -> 10.4.20

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Release Notes

postcss/autoprefixer (autoprefixer)

### [`v10.4.20`](https://togithub.com/postcss/autoprefixer/blob/HEAD/CHANGELOG.md#10420) [Compare Source](https://togithub.com/postcss/autoprefixer/compare/10.4.19...10.4.20) - Fixed `fit-content` prefix for Firefox.

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Configuration

📅 Schedule: Branch creation - "on sunday before 6:00am" in timezone UTC, Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• [ ] If you want to rebase/retry this PR, check this box

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