Bump postcss from 8.5.4 to 8.5.6

Bumps [postcss](https://github.com/postcss/postcss) from 8.5.4 to 8.5.6.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/8.5.4...8.5.6)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.6
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

yarn.lock

@@ -12402,14 +12402,14 @@ __metadata:
   languageName: node
   linkType: hard
 
-"postcss@npm:^8.5.4":
-  version: 8.5.4
-  resolution: "postcss@npm:8.5.4"
+"postcss@npm:^8.5.6":
+  version: 8.5.6
+  resolution: "postcss@npm:8.5.6"
   dependencies:
     nanoid: "npm:^3.3.11"
     picocolors: "npm:^1.1.1"
     source-map-js: "npm:^1.2.1"
-  checksum: 10c0/0feff648614a834f7cd5396ea6b05b658ca0507e10a4eaad03b56c348f6aec93f42a885fc1b30522630c6a7e49ae53b38a061e3cba526f2d9857afbe095a22bb
+  checksum: 10c0/5127cc7c91ed7a133a1b7318012d8bfa112da9ef092dddf369ae699a1f10ebbd89b1b9f25f3228795b84585c72aabd5ced5fc11f2ba467eedf7b081a66fad024
   languageName: node
   linkType: hard
 
@@ -14309,7 +14309,7 @@ __metadata:
     lucide-react: "npm:^0.514.0"
     next: "npm:^15.3.2"
     next-themes: "npm:^0.4.6"
-    postcss: "npm:^8.5.4"
+    postcss: "npm:^8.5.6"
     prettier: "npm:^3.5.3"
     prettier-plugin-tailwindcss: "npm:^0.6.11"
     prisma: "npm:^6.5.0"