chore(deps-dev): bump postcss from 8.4.16 to 8.4.18

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.16 to 8.4.18.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.16...8.4.18)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

package.json

@@ -59,7 +59,7 @@
     "grunt-uncss-inline": "1.2.7",
     "grunt-xmlmin": "0.1.8",
     "jit-grunt": "0.10.0",
-    "postcss": "8.4.16",
+    "postcss": "8.4.18",
     "sass": "1.54.5",
     "terser": "5.15.0"
   },

yarn.lock

@@ -3510,10 +3510,10 @@ postcss-value-parser@^4.2.0:
   resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-4.2.0.tgz#723c09920836ba6d3e5af019f92bc0971c02e514"
   integrity sha512-1NNCs6uurfkVbeXG4S8JFT9t19m45ICnif8zWLd5oPSZ50QnwMfK+H3jv408d4jw/7Bttv5axS5IiHoLaVNHeQ==
 
-[email protected].16:
-  version "8.4.16"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.16.tgz#33a1d675fac39941f5f445db0de4db2b6e01d43c"
-  integrity sha512-ipHE1XBvKzm5xI7hiHCZJCSugxvsdq2mPnsq5+UF+VHCjiBvtDrlxJfMBToWaP9D5XlgNmcFGqoHmUn0EYEaRQ==
+[email protected].18:
+  version "8.4.18"
+  resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.18.tgz#6d50046ea7d3d66a85e0e782074e7203bc7fbca2"
+  integrity sha512-Wi8mWhncLJm11GATDaQKobXSNEYGUHeQLiQqDFG1qQ5UTDPTEvKw0Xt5NsTpktGTwLps3ByrWsBrG0rB8YQ9oA==
   dependencies:
     nanoid "^3.3.4"
     picocolors "^1.0.0"