Update dependency postcss to v8.5.3 (#2034)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [postcss](https://postcss.org/)
([source](https://redirect.github.com/postcss/postcss)) | dependencies |
patch | [`8.5.2` ->
`8.5.3`](https://renovatebot.com/diffs/npm/postcss/8.5.2/8.5.3) |

---

> [!WARNING]
> Some dependencies could not be looked up. Check the Dependency
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---

### Release Notes

<details>
<summary>postcss/postcss (postcss)</summary>

###
[`v8.5.3`](https://redirect.github.com/postcss/postcss/blob/HEAD/CHANGELOG.md#853)

[Compare
Source](https://redirect.github.com/postcss/postcss/compare/8.5.2...8.5.3)

- Added more details to `Unknown word` error (by
[@&#8203;hiepxanh](https://redirect.github.com/hiepxanh)).
- Fixed types (by
[@&#8203;romainmenke](https://redirect.github.com/romainmenke)).
- Fixed docs (by
[@&#8203;catnipan](https://redirect.github.com/catnipan)).

</details>

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aws-ts-nextjs/demoapp/package.json

@@ -16,7 +16,7 @@
     "eslint": "9.21.0",
     "eslint-config-next": "15.1.7",
     "next": "15.1.7",
-    "postcss": "8.5.2",
+    "postcss": "8.5.3",
     "react": "19.0.0",
     "react-dom": "19.0.0",
     "tailwindcss": "3.4.17",