Update GitHub CI workflow

Author: drewnoakes

.github/workflows/CI.yml

@@ -4,36 +4,47 @@ on: [push, pull_request]
 jobs:
   ununtu:
     runs-on: ubuntu-latest
+    env:
+      DOTNET_NOLOGO: true
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: |
+          3.1.x
+          6.0.x
     - run: dotnet restore src/NetMQ.sln
     - name: build 
       run: dotnet build src/NetMQ.sln /p:Configuration=Release /verbosity:minimal
     - name: test netcoreapp3.1
       run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f netcoreapp3.1 src/NetMQ.Tests/NetMQ.Tests.csproj
-    - name: test netcoreapp2.1
-      run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f netcoreapp2.1 src/NetMQ.Tests/NetMQ.Tests.csproj
+    - name: test net6.0
+      run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f net6.0 src/NetMQ.Tests/NetMQ.Tests.csproj
   windows:
     runs-on: windows-latest
+    env:
+      DOTNET_NOLOGO: true
     steps:
     - uses: actions/checkout@v2
+    - uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: |
+          3.1.x
+          6.0.x
     - name: Install codecov
       run: |
         choco install opencover.portable 
         choco install codecov
     - run: dotnet restore src/NetMQ.sln
     - name: build 
       run: dotnet build src/NetMQ.sln /p:Configuration=Release /verbosity:minimal
-    - name: test netcoreapp2.1
-      run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f netcoreapp2.1 src\NetMQ.Tests\NetMQ.Tests.csproj
+    - name: test net6.0
+      run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f net6.0 src\NetMQ.Tests\NetMQ.Tests.csproj
     - name: test netcoreapp3.1
       run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f netcoreapp3.1 src\NetMQ.Tests\NetMQ.Tests.csproj
     - name: test net47
       run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f net47 src\NetMQ.Tests\NetMQ.Tests.csproj
     - name: coverage
       run: |
-        OpenCover.Console.exe -register:user -target:"C:\Program Files\dotnet\dotnet.exe" -targetargs:"test --no-build --configuration Release -f netcoreapp2.1 --logger:trx;LogFileName=results.trx /p:DebugType=full src\NetMQ.Tests\NetMQ.Tests.csproj" -filter:"+[NetMQ*]* -[NetMQ.Tests*]*" -output:".\NetMQ_coverage.xml" -oldStyle
+        OpenCover.Console.exe -register:user -target:"C:\Program Files\dotnet\dotnet.exe" -targetargs:"test --no-build --configuration Release -f net6.0 --logger:trx;LogFileName=results.trx /p:DebugType=full src\NetMQ.Tests\NetMQ.Tests.csproj" -filter:"+[NetMQ*]* -[NetMQ.Tests*]*" -output:".\NetMQ_coverage.xml" -oldStyle
         codecov -f "NetMQ_coverage.xml"
-       
-       
-