Bump postcss from 8.3.11 to 8.4.6

Bumps [postcss](https://github.com/postcss/postcss) from 8.3.11 to 8.4.6.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.3.11...8.4.6)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package.json

@@ -20,7 +20,7 @@
 	"homepage": "https://www.faucet-pipeline.org",
 	"dependencies": {
 		"faucet-pipeline-core": "^1.6.1",
-		"postcss": "~8.3.0",
+		"postcss": "~8.4.6",
 		"postcss-discard-comments": "~5.0.1",
 		"postcss-import": "~14.0.2",
 		"postcss-message-helpers": "~2.0.0",