Test on supported .NET SDKs

Author: AArnott

azure-pipelines.yml

@@ -21,18 +21,14 @@ parameters:
 
 resources:
   containers:
-  - container: focal
-    image: mcr.microsoft.com/dotnet/sdk:6.0-focal
-  - container: jammy60
-    image: mcr.microsoft.com/dotnet/sdk:6.0-jammy
-  - container: jammy70
-    image: mcr.microsoft.com/dotnet/sdk:7.0-jammy
   - container: jammy80
     image: mcr.microsoft.com/dotnet/sdk:8.0-jammy
-  - container: debian70
-    image: mcr.microsoft.com/dotnet/sdk:7.0
+  - container: noble90
+    image: mcr.microsoft.com/dotnet/sdk:9.0-noble
   - container: debian80
     image: mcr.microsoft.com/dotnet/sdk:8.0
+  - container: debian90
+    image: mcr.microsoft.com/dotnet/sdk:9.0
 
 variables:
   DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true