[release-tool] test coverage

[radTuti]

Description

This add unit tests to a couple functions in the release tool.

Related issues/PRs

Todos

• Tests
• Documentation
• Release note

Release Note

TBD

Reminder for the reviewer

Make sure that this PR has the correct labels and milestone set.

Every PR needs one docs-* label.

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• release-note-not-required: This PR has no user-facing changes.

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[Copilot]

Pull Request Overview

This PR enhances test coverage and refines underlying utility functions for the release tool. Key changes include:

• Addition of unit tests for version determination, component formatting, release notes generation, and image scanning.
• Improvements to error handling, logging, and file output in the image scanner, as well as refinements in CI configuration and Makefile targets.
• Updates to the CI semaphore configuration and .gitignore to support the new test report artifacts.

Reviewed Changes

Copilot reviewed 15 out of 17 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
release/internal/version/version_test.go	Added multiple test cases for version stream and branching logic.
release/internal/registry/component_test.go	Introduced tests for component string and init image generation.
release/internal/outputs/templates/release-note.md.gotmpl	Adjusted template formatting for bug fixes and other changes.
release/internal/outputs/releasenotes_test.go	Added approval tests to verify release notes output.
release/internal/imagescanner/scanner_test.go	Expanded tests to cover various scanner configurations and HTTP responses.
release/internal/imagescanner/scanner.go	Refined error handling and ensured proper resource cleanup on scan.
release/internal/ci/semaphore.go	Updated URL building using url.JoinPath and improved promotion filtering logic.
release/Makefile	Enhanced unit test target to generate JUnit reports and installed gotestsum.
release/.gitignore	Added new ignore patterns for test reports and approval test artifacts.
go.mod	Added dependency for go-approval-tests.
.semaphore/*.yml	Updated CI configuration to publish unit-test reports.

Comments suppressed due to low confidence (1)

release/internal/ci/semaphore.go:39

• The local variable 'url' shadows the imported package 'net/url'. Consider renaming the variable (e.g., promotionsURL) to avoid confusion.

	url, err := url.JoinPath(orgURL, "promotions")