chore: replace some references, go mod tidy (DBAAS-5097)

[splicemaahs]

Just some cleanup of references to another project source for the "changelog" builder

Description

Purely reference changes and run go mod tidy.

Motivation and Context

go was complaining because it couldn't access referenced material. This was specifically in the changelog generation code, nothing specifically with splicectl code.

Changelog Inclusions

Additions

Changes

• reference changes for building changelogs

Fixes

Deprecated

Removed

Checklist

If the pull request includes user-facing changes, extra documentation is required:

• Add a new changelog fragment in changelog/fragments (see changelog/fragments/00-template.yaml)

• Reviewed and no changelog fragment required

  • It is important to include the changelog fragment in your PR, this way the changelog will include the correct PR link.

[voron]

LGTM