Updated CI jobs to use .net6 compatible images (hopefully).

Author: sipsorcery

.appveyor-ubuntu.yml

@@ -17,6 +17,7 @@ build_script:
 test_script:
 - dotnet test test/unit/SIPSorcery.UnitTests.csproj -c Release --framework netcoreapp3.1
 - dotnet test test/unit/SIPSorcery.UnitTests.csproj -c Release --framework net5
+- dotnet test test/unit/SIPSorcery.UnitTests.csproj -c Release --framework net6
 #on_finish:
 #  - sh: export APPVEYOR_SSH_BLOCK=true
 #  - sh: curl -sflL 'https://raw.githubusercontent.com/appveyor/ci/master/scripts/enable-ssh.sh' | bash -e -

.appveyor-wsl.yml

@@ -17,5 +17,5 @@ build_script:
        wsl sudo apt-get update -y
        wsl sudo apt-get install -y apt-transport-https
        wsl sudo apt-get update -y
-       wsl sudo apt-get install -y dotnet-sdk-3.1
+       wsl sudo apt-get install -y dotnet-sdk-6.0
        wsl dotnet test test/unit/SIPSorcery.UnitTests.csproj -c Release --framework netcoreapp3.1

.appveyor.yml

@@ -9,7 +9,7 @@ environment:
   access_token:
     # Token for github pages publishing.
     secure: vhHzssxBhg0t4JAiWZZ1r/RTzsbKcGn16cxj7uBoPVVEJSaLaJ+gOdaUdsfX2ooI
-image: Visual Studio 2019
+image: Visual Studio 2022
 configuration: Release
 before_build:
 - cmd: nuget restore -DisableParallelProcessing src\SIPSorcery.sln

.github/workflows/sipsorcery-core-win.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   build:
-    runs-on: windows-latest
+    runs-on: windows-2022
     name: dotnet windows sipsorcery core
     steps:
     - uses: actions/checkout@v2