Update ci.yml

Author: ivailop

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ on:
 
 jobs:
   build:
-    runs-on: windows-2019
+    runs-on: windows-2016
     steps:
       - uses: nuget/setup-nuget@v1
       - uses: microsoft/setup-msbuild@v1