build(deps): bump postcss from 8.2.7 to 8.2.8

Bumps [postcss](https://github.com/postcss/postcss) from 8.2.7 to 8.2.8.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.2.7...8.2.8)

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

package.json

@@ -58,7 +58,7 @@
     "ncp": "^2.0.0",
     "node-version-data": "^1.1.0",
     "npm-run-all": "^4.1.5",
-    "postcss": "^8.2.7",
+    "postcss": "^8.2.8",
     "sass": "^1.32.8",
     "semver": "^7.3.4",
     "strftime": "^0.10.0"