Fix npm audit findings in postcss and react-router

Bump postcss to 8.5.23 and react-router to 8.3.0 to clear their high-severity advisories. Leave nested brace-expansion issues for a follow-up that won't break older minimatch consumers.

Signed-off-by: Sacha Al Himdani <sacha@probo.com>

packages/relay/package.json

@@ -18,7 +18,7 @@
   "peerDependencies": {
     "react": "^19.2.7",
     "react-relay": "^21.0.1",
-    "react-router": "^8.1.0",
+    "react-router": "^8.3.0",
     "relay-runtime": "^21.0.1"
   },
   "dependencies": {

packages/routes/package.json

@@ -17,7 +17,7 @@
   "peerDependencies": {
     "react": "^19.2.7",
     "react-relay": "^21.0.1",
-    "react-router": "^8.1.0",
+    "react-router": "^8.3.0",
     "relay-runtime": "^21.0.1"
   }
 }

packages/ui/package.json

@@ -66,7 +66,7 @@
     "react": "^19.2.7",
     "react-docgen": "^8.0.3",
     "react-dom": "^19.2.7",
-    "react-router": "^8.1.0",
+    "react-router": "^8.3.0",
     "storybook": "^10.2.10",
     "typescript": "~6.0.3",
     "vite": "^8.1.2",
@@ -75,7 +75,7 @@
   "peerDependencies": {
     "react": "^19.2.7",
     "react-dom": "^19.2.7",
-    "react-router": "^8.1.0"
+    "react-router": "^8.3.0"
   },
   "volta": {
     "node": "24.4.0"