Set environment variables

appveyor.yml

@@ -10,6 +10,9 @@ assembly_info:
   file: 'Properties\AssemblyInfo.cs'
   assembly_version: "{version}"
   assembly_file_version: "{version}"
+environment:
+  DOTNET_NOLOGO: true
+  DOTNET_CLI_TELEMETRY_OPTOUT: 1
 install:
 - ps: |
     Invoke-WebRequest -Uri 'https://dot.net/v1/dotnet-install.ps1' -UseBasicParsing -OutFile "$env:temp\dotnet-install.ps1"