SDK Diff Pipeline not triggering for 8.0 and 9.0

[ellahathaway]

The SDK diff pipeline currently uses the YAML from the main branch of the dotnet-dotnet repository. This YAML references the dotnet-unified-build pipeline, meaning that SDK diff builds are only triggered by builds from the unified-build pipeline, regardless of the branch. As a result, because 8.0 and 9.0 are not being built via the dotnet-unified-build pipeline, the SDK diff pipeline isn’t being triggered for these branches.

Interestingly, there was a successful dotnet-unified-build build on the internal/release/8.0.1xx branch on May 14 (see this build), which did trigger the SDK diff pipeline. If this wasn’t a one-off, we might want to consider consistently running source-build jobs from the unified-build pipeline and renaming the pipeline to something more generic, like dotnet-build.