chore(deps): update actions/setup-node action to v4

Author: renovate[bot]

.github/workflows/pr-checks.yml

@@ -59,7 +59,7 @@ jobs:
 
       # Use ajv to validate schema
       - name: Setup node
-        uses: actions/setup-node@v3.8.1
+        uses: actions/setup-node@v4.0.0
 
       - name: Validate schema 
         run: make ajv-validate-flagd-schema