deps: bump postcss

Bumps the npm_and_yarn group with 1 update in the /samples/react/login-pkce directory: [postcss](https://github.com/postcss/postcss).


Updates `postcss` from 8.5.9 to 8.5.12
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.5.9...8.5.12)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.5.12
  dependency-type: indirect
  dependency-group: npm_and_yarn
...

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

Author: dependabot[bot]

samples/react/login-pkce/yarn.lock

@@ -1397,25 +1397,14 @@ __metadata:
   languageName: node
   linkType: hard
 
-"postcss@npm:^8.5.10":
-  version: 8.5.10
-  resolution: "postcss@npm:8.5.10"
+"postcss@npm:^8.5.10, postcss@npm:^8.5.8":
+  version: 8.5.12
+  resolution: "postcss@npm:8.5.12"
   dependencies:
     nanoid: "npm:^3.3.11"
     picocolors: "npm:^1.1.1"
     source-map-js: "npm:^1.2.1"
-  checksum: 10c0/c592dffa0c4873b401f01955b265538d9942f425040df5e2b8f0ad34c83773a792ea0fa5859ccc99cfb5b955b4ebff118ab7056315388dc83b107b0fa8313576
-  languageName: node
-  linkType: hard
-
-"postcss@npm:^8.5.8":
-  version: 8.5.9
-  resolution: "postcss@npm:8.5.9"
-  dependencies:
-    nanoid: "npm:^3.3.11"
-    picocolors: "npm:^1.1.1"
-    source-map-js: "npm:^1.2.1"
-  checksum: 10c0/7cb2b32202ea1ead03f15cfbb2756a64a0f98942378e99b3dfce33678fe5eaf93e31d675a46e3a0dfb417d7b49b82d8999d0dd42a33c3b128e71ade0f978719a
+  checksum: 10c0/5baebaf574c567bc1b3d61197f38af4ce5920b8f611c887fb6bc3dcc14af00253c169dbf19897bc889cce0b0d9818ab5eb4ea0caedf02b0bab10da8a43ce8c12
   languageName: node
   linkType: hard