Piipeline fix for dotnet versions in ubuntu-latest (redis#372)

pipeline fix

Author: atakavci

.github/workflows/reusable.yml

@@ -37,7 +37,10 @@ jobs:
           - name: .NET Core 8
             uses: actions/setup-dotnet@v3
             with:
-              dotnet-version: 8
+              dotnet-version: |
+                6
+                7
+                8
 
           - name: Run redis-stack-server docker
             working-directory: .github