add net6 targets (#745)

* add net6 targets

* move to net6 builtin format

* e2e target

* make codeql happy

.github/workflows/codeql-analysis.yml

@@ -25,6 +25,19 @@ jobs:
       with:
           fetch-depth: 0
 
+    - name: Setup dotnet SDK 3.1
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: '3.1.x'          
+    - name: Setup dotnet SDK 5
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: '5.0.x'                
+    - name: Setup dotnet SDK 6
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: '6.0.x'               
+
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v1