Update ci.yml - added dotnet 9 setup

Author: TimurRybakov

.github/workflows/ci.yml

@@ -11,18 +11,21 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    
     steps:
 
     - name: Checkout
       uses: actions/checkout@v2
       with:
         fetch-depth: 0
 
-    - name: Setup dotnet 8.0
+    - name: Setup dotnet
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: '8.0.100'
-
+        dotnet-version: |
+          8.0.x
+          9.0.x
+          
     - name: Clean
       run: dotnet clean -c Release