Support .NET 9.0

[samruddhikhandale]

• Open a PR
• Create a release
• Update templates (if necessary)
• Update [Tracking] Image support, deprecation / EOL dates #90
• Update Microsoft Artifact Registry docs

[gauravsaini04]

Templates - devcontainers/templates#288
MCR Docs - https://github.com/microsoft/mcrdocs/pull/47538

[gauravsaini04]

Templates and MCR docs PR's have been merged for this issue.

[gauravsaini04]

• Open a PR
• Create a release
• Update templates (if necessary)
• Update [Tracking] Image support, deprecation / EOL dates #90
• Update Microsoft Artifact Registry docs

[mitchdenny]

The .NET 9.0 GA container images are live, the dev container images should be rebuilt now.

[hansmbakker]

When I create a .NET 9 devcontainer now it seems the .NET 9 RC2 SDK is used - can you please publish an image using the GA version?

[m-a-parent]

Like @hansmbakker mentioned the 9.0 images do not have the released SDK version 9.100.0 installed.
For example, the devcontainer mcr.microsoft.com/devcontainers/dotnet:1-9.0 image contains dotnet version: 9.0.100-rc.2.24474.11.
When I build my project in a devcontainer based on that image I get:
/usr/share/dotnet/sdk/9.0.100-rc.2.24474.11/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.RuntimeIdentifierInference.targets(326,5): message NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy [path_to_my_project_csproj_file]
Does anyone know when the 9.0 devcontainer images will be updated to SDK version 9.100.0?

[TomasEkeli]

any update on this?

a freshly built devcontainer still has v 9.0.100-rc.2

vscode ➜ /workspaces/tmp $ dotnet --version
9.0.100-rc.2.24474.11

[m-a-parent]

I hoped that @samruddhikhandale or @gauravsaini04 would have commented by now. I figure they should know what is going on since they're the assignees on this issue.