Update ci.yml

Author: GlebChili

.github/workflows/ci.yml

@@ -329,6 +329,11 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v2.3.4
 
+      - name: Setup .NET Core SDK (old)
+        uses: actions/setup-dotnet@v1.7.2
+        with:
+          dotnet-version: 5.0.202
+
       - name: Setup .NET Core SDK
         uses: actions/setup-dotnet@v1.8.1