fixing dotnet SDK version in GitHub Actions

Author: aryonoco

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3
       with:
-        dotnet-version: '8.0.x'
+        dotnet-version: '9.0.x'
 
     - name: Restore dependencies
       run: dotnet restore
@@ -42,7 +42,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3
       with:
-        dotnet-version: '8.0.x'
+        dotnet-version: '9.0.x'
 
     - name: Restore dependencies
       run: dotnet restore
@@ -70,7 +70,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v3
       with:
-        dotnet-version: '8.0.x'
+        dotnet-version: '9.0.x'
 
     - name: Publish ${{ matrix.runtime }}
       run: |