force dotnet version

Author: jinliu9508

.github/workflows/create-release-pr.yml

@@ -59,6 +59,18 @@ jobs:
         with:
           dotnet-version: '8.0.x'
 
+      - name: Force .NET 8 SDK pinning
+        run: |
+          echo '{
+            "sdk": {
+              "version": "8.0.403",
+              "rollForward": "disable"
+            }
+          }' > global.json
+
+      - name: Confirm SDK version
+        run: dotnet --info
+
       - name: Cache .NET workloads
         id: dotnet-workload-cache
         uses: actions/cache@v4