Update-dependencies pipeline: create separate PRs per upgraded image component

[lbussell]

Describe the Problem

The Update-dependencies tool, via our pipelines, creates one pull request per day if there are any components that should be upgraded. This usually bundles together .NET updates along with updates to other tools or image components, like syft, mingit, or chisel.

When all components are updated together in one PR and one commit it is more difficult to isolate the cause of PR validation failures. Furthermore, merging all of the changes together provides less detail in the commit history about what versions were updated at which times.

Describe the Solution

In the update-dependencies pipeline, we should submit separate PRs for each of the tools listed above and keep them separate from .NET updates.

[lbussell]

[Triage] This is completed with #6122.