Update linux_x64_dev_innerloop container to Ubuntu 26.04

[Copilot]

Updates the linux_x64_dev_innerloop container image reference from Ubuntu 24.04 to 26.04 with architecture suffix in the pipeline resources template.

Changes:

• Updated eng/pipelines/common/templates/pipeline-with-resources.yml line 67 from ubuntu-24.04 to ubuntu-26.04-amd64

This aligns with Ubuntu 26.04 already being used for Helix queues and other pipeline configurations throughout the repository, and follows the new pattern of including architecture suffixes in image tags.

Original prompt

Please update this reference to Ubuntu 26.04.

https://github.com/dotnet/runtime/blob/main/eng/pipelines/common/templates/pipeline-with-resources.yml#L67

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[richlander]

@copilot Please add architecture to the tag: ubuntu-26.04-amd64. That's the new pattern.

[Copilot]

@copilot Please add architecture to the tag: ubuntu-26.04-amd64. That's the new pattern.

Updated to ubuntu-26.04-amd64 in commit a1e2537.

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[jkoritzinsky]

I'd like to wait to accept this until 26.04 is actually released. The legs that use this docker image is meant to represent the inner dev loop for developers on the team on Linux.

I find it unlikely that a significant portion of the contributors to this repo that work on Linux in some capacity (whether WSL, VM, or on a real Linux box) are on Ubuntu 26.04 as it hasn't released yet.

[richlander]

That's a fair view. There are two other views:

• The branch has moved to Ubuntu 26.04
• The branch needs to prepare for Ubuntu 26.04 GA

That all said, I understand this particular leg less well than the other ones. If you are not compelled, we/you can close this PR.

[jkoritzinsky]

I think it's more important to protect the dev experience, at least until Ubuntu 26.04 is released. I don't feel comfortable stating that Ubuntu 26.04 is our "supported" Linux dev environment until Canonical sees it as release quality (ie running sudo do-release-upgrade on an Ubuntu 24.04 system recommends the upgrade to Ubuntu 26.04). I feel this way because I don't think the right answer to "my build doesn't work on Ubuntu 24.04 LTS" is "upgrade to a development snapshot of Ubuntu 26.04".

I think moving our "latest glibc Linux" Helix runs to use 26.04 makes sense and that will get us much more interesting validation.

[richlander]

I'll leave the decision to you. If someone else has a contrary view, it is easy to re-open the discussion/PR.

Also, the 26.04 image is now ready when we need it.