[INFRA] dev - Bump postcss from 8.2.2 to 8.2.4 (#1016)

Bumps [postcss](https://github.com/postcss/postcss) from 8.2.2 to 8.2.4.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.2.2...8.2.4)

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -115,7 +115,7 @@
     "minimist": "^1.2.5",
     "mxgraph-type-definitions": "^1.0.4",
     "npm-run-all": "^4.1.5",
-    "postcss": "^8.2.2",
+    "postcss": "^8.2.4",
     "postcss-cli": "^8.3.1",
     "prettier": "^2.2.1",
     "puppeteer": "^5.5.0",