fix(deps): update dependency postcss to v8.4.28 (#439)

[![Mend Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [postcss](https://postcss.org/) ([source](https://github.com/postcss/postcss)) | [`8.4.27` -> `8.4.28`](https://renovatebot.com/diffs/npm/postcss/8.4.27/8.4.28) | [![age](https://developer.mend.io/api/mc/badges/age/npm/postcss/8.4.28?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://developer.mend.io/api/mc/badges/adoption/npm/postcss/8.4.28?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://developer.mend.io/api/mc/badges/compatibility/npm/postcss/8.4.27/8.4.28?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/postcss/8.4.27/8.4.28?slim=true)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

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

### [`v8.4.28`](https://github.com/postcss/postcss/blob/HEAD/CHANGELOG.md#8428)

[Compare Source](https://github.com/postcss/postcss/compare/8.4.27...8.4.28)

-   Fixed `Root.source.end` for better source map (by Romain Menke).
-   Fixed `Result.root` types when `process()` has no parser.

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), 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.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Mend Renovate](https://www.mend.io/free-developer-tools/renovate/). View repository job log [here](https://developer.mend.io/github/kula-app/OnLaunch).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNi40My4yIiwidXBkYXRlZEluVmVyIjoiMzYuNDMuMiIsInRhcmdldEJyYW5jaCI6Im1haW4ifQ==-->

yarn.lock

@@ -7950,9 +7950,9 @@ postcss@8.4.14:
     source-map-js "^1.0.2"
 
 postcss@^8.4.23, postcss@^8.4.24:
-  version "8.4.27"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.27.tgz#234d7e4b72e34ba5a92c29636734349e0d9c3057"
-  integrity sha512-gY/ACJtJPSmUFPDCHtX78+01fHa64FaU4zaaWfuh1MhGJISufJAH4cun6k/8fwsHYeK4UQmENQK+tRLCFJE8JQ==
+  version "8.4.28"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.28.tgz#c6cc681ed00109072816e1557f889ef51cf950a5"
+  integrity sha512-Z7V5j0cq8oEKyejIKfpD8b4eBy9cwW2JWPk0+fB1HOAMsfHbnAXLLS+PfVWlzMSLQaWttKDt607I0XHmpE67Vw==
   dependencies:
     nanoid "^3.3.6"
     picocolors "^1.0.0"