Bump postcss from 8.4.18 to 8.4.31 (#79)

Bumps [postcss](https://github.com/postcss/postcss) from 8.4.18 to 8.4.31.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.18...8.4.31)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -31,7 +31,7 @@
         "@types/react-syntax-highlighter": "15.5.5",
         "autoprefixer": "10.4.13",
         "next": "13.0.2",
-        "postcss": "8.4.18",
+        "postcss": "8.4.31",
         "prettier": "2.7.1",
         "tailwindcss": "3.2.2",
         "typescript": "4.8.4"

yarn.lock

@@ -1391,7 +1391,7 @@ __metadata:
     autoprefixer: 10.4.13
     github-markdown-css: 5.1.0
     next: 13.0.2
-    postcss: 8.4.18
+    postcss: 8.4.31
     prettier: 2.7.1
     react: 18.2.0
     react-dom: 18.2.0
@@ -1624,6 +1624,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"nanoid@npm:^3.3.6":
+  version: 3.3.6
+  resolution: "nanoid@npm:3.3.6"
+  bin:
+    nanoid: bin/nanoid.cjs
+  checksum: 7d0eda657002738aa5206107bd0580aead6c95c460ef1bdd0b1a87a9c7ae6277ac2e9b945306aaa5b32c6dcb7feaf462d0f552e7f8b5718abfc6ead5c94a71b3
+  languageName: node
+  linkType: hard
+
 "negotiator@npm:^0.6.3":
   version: 0.6.3
   resolution: "negotiator@npm:0.6.3"
@@ -1944,7 +1953,18 @@ __metadata:
   languageName: node
   linkType: hard
 
-"postcss@npm:8.4.18, postcss@npm:^8.4.18":
+"postcss@npm:8.4.31":
+  version: 8.4.31
+  resolution: "postcss@npm:8.4.31"
+  dependencies:
+    nanoid: ^3.3.6
+    picocolors: ^1.0.0
+    source-map-js: ^1.0.2
+  checksum: 1d8611341b073143ad90486fcdfeab49edd243377b1f51834dc4f6d028e82ce5190e4f11bb2633276864503654fb7cab28e67abdc0fbf9d1f88cad4a0ff0beea
+  languageName: node
+  linkType: hard
+
+"postcss@npm:^8.4.18":
   version: 8.4.18
   resolution: "postcss@npm:8.4.18"
   dependencies: