Fix CI (#1001)

Author: Shane32

.github/workflows/build.yml

@@ -20,7 +20,9 @@ jobs:
       - name: Setup .NET SDK
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: 7.0.x
+          dotnet-version: |
+            6.0.x
+            7.0.x
           source-url: https://nuget.pkg.github.com/graphql-dotnet/index.json
         env:
           NUGET_AUTH_TOKEN: ${{secrets.GITHUB_TOKEN}}

.github/workflows/publish.yml

@@ -30,7 +30,9 @@ jobs:
       - name: Setup .NET SDK
         uses: actions/setup-dotnet@v1
         with:
-          dotnet-version: 7.0.x
+          dotnet-version: |
+            6.0.x
+            7.0.x
           source-url: https://api.nuget.org/v3/index.json
         env:
           NUGET_AUTH_TOKEN: ${{secrets.NUGET_AUTH_TOKEN}}