(build) ignore Microsoft.Build updates for 3.1 and 5.0

Author: arturcic

.github/dependabot.yml

@@ -9,6 +9,9 @@ updates:
   schedule:
     interval: daily
   open-pull-requests-limit: 10
+  ignore:
+    - dependency-name: "Microsoft.Build"
+      versions: ["16.9.0", "16.11.0"]
 - package-ecosystem: github-actions
   labels:
     - "dependencies"