Revert "Update appveyor.yml"

This reverts commit 4207439.

Author: SimonCropp

src/appveyor.yml

@@ -7,7 +7,6 @@ environment:
   DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
 build_script:
 - pwsh: |
-    dotnet workload restore
     if ($isWindows) {
       Invoke-WebRequest "https://dot.net/v1/dotnet-install.ps1" -OutFile "./dotnet-install.ps1"
       ./dotnet-install.ps1 -JSonFile src/global.json -Architecture x64 -InstallDir 'C:\Program Files\dotnet'