Fix package builds

Author: deanward81

.github/workflows/packages.yml

@@ -31,6 +31,8 @@ jobs:
       uses: actions/checkout@v2
       with:
         fetch-depth: 0
+    - name: Install .NET SDK
+      uses: actions/setup-dotnet@v1
     - name: .NET Build
       run: dotnet build Build.csproj -c Release --nologo /p:CI=true
     - name: .NET Test