Update dependency postcss to v8.5.6

This MR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
postcss (source)	8.5.1 -> 8.5.6

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⚠️ Warning

Some dependencies could not be looked up. Check the Dependency Dashboard for more information.

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Release Notes

postcss/postcss (postcss)

v8.5.6

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v8.5.5

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v8.5.4

Compare Source

v8.5.3

Compare Source

v8.5.2

Compare Source

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