Adapt production branch names to 1ES standards

[qmuntal]

Production pipelines can only be triggered from production branches, as per this doc: https://eng.ms/docs/cloud-ai-platform/devdiv/one-engineering-system-1es/1es-docs/1es-pipeline-templates/features/releasepipelines/release-features/release-gating#branch-validation-1es-pt.

Production branches are autodetected by inspecting the name, which should follow an standard pattern. We currently name our production branches following the microsoft/release-branch.go* pattern, which is not in the official list.

#1522 added a configuration file to the repo so that 1ES detects our release branches as production branches.

We should consider adopting the official naming convention instead of using our own.

[dagood]

• Related: https://github.com/microsoft/go-lab/issues/166

[dagood]

We talked about it a bit in our last sync--I propose:

microsoft/main -> main
microsoft/release-branch.go1.23 -> release/1.23 (e.g.)

release/1.23 is what I'm used to from .NET, and I like how concise it is. release/go1.23 would also seem like a good fit to me while sticking a bit closer to upstream.

As a historical note, the microsoft/ prefix is because microsoft/go was originally a simple Git fork, and we needed a way to differentiate our branches from upstream's. (This has to do with decisions described in https://github.com/microsoft/go-infra/tree/7e98b104065d18707637dd00d62d371aaa6247ad/docs/fork, but I don't think we've directly documented the history of it.)