support net 9 in ci

Author: lofcz

.github/workflows/dotnet.yml

@@ -13,6 +13,9 @@ permissions:
 jobs:
   build-and-test:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        dotnet-version: ['8.0.203', '9.0.101'] 
 
     steps:
     - name: Checkout repository
@@ -21,7 +24,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: 8.0.203
+        dotnet-version: ${{ matrix.dotnet-version }}
 
     - name: Setup Node.js
       uses: actions/setup-node@v3