Update .NET SDK

Update .NET SDK to version 6.0.403.

---
updated-dependencies:
- dependency-name: Microsoft.NET.Sdk
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Author: github-actions[bot]

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "6.0.402",
+    "version": "6.0.403",
     "allowPrerelease": false,
     "rollForward": "latestMajor"
   }