Specify VS version when setting up msbuild

Author: christianhelle

.github/workflows/vsix.yml

@@ -46,6 +46,8 @@ jobs:
 
     - name: Setup MSBuild.exe
       uses: microsoft/setup-msbuild@v2
+      with:
+        vs-version: '[16.4,16.5)'
 
     - name: Build
       run: msbuild VSIX.sln /property:Configuration=Release /p:DeployExtension=false