Modify build.yml

.github/workflows/build.yml

@@ -7,6 +7,13 @@ jobs:
       - name: checkout
         uses: actions/checkout@master
       
+      - name: Install .NET 60
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: '6.0'
+        include-prerelease: True
+
+
       - name: build
         shell: pwsh
         run: |