build: strip YAML frontmatter from breaking changes in changelog

[Planeshifter]

Description

What is the purpose of this pull request?

This pull request:

• updates changelog generation to remove YAML blocks from display of breaking changes

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves [RFC]: strip YAML blocks from commit messages during changelog generation metr-issue-tracker#53.

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

Previously, output could include YAML metadata in breaking changes display. Here is an example:

-   [`39e505f`](https://github.com/stdlib-js/stdlib/commit/39e505f50432543c5e6c76c85392e59846ce58c6): remove `math/base/ops/csubf`

    -   To migrate, users should update their require/import paths to use
        `@stdlib/complex/float32/base/sub` which provides the same API and
        implementation.
        Ref: https://github.com/stdlib-js/stdlib/issues/2261
        ---
        type: pre_commit_static_analysis_report
        description: Results of running static analysis checks when committing changes.
        report:
          - task: lint_filenames
            status: passed
          - task: lint_editorconfig
            status: passed
          - task: lint_markdown
            status: na
          - task: lint_package_json
            status: na
          - task: lint_repl_help
            status: na
          - task: lint_javascript_src
            status: na
          - task: lint_javascript_cli
            status: na
          - task: lint_javascript_examples
            status: na
          - task: lint_javascript_tests
            status: na
          - task: lint_javascript_benchmarks
            status: na
          - task: lint_python
            status: na
          - task: lint_r
            status: na
          - task: lint_c_src
            status: na
          - task: lint_c_examples
            status: na
          - task: lint_c_benchmarks
            status: na
          - task: lint_c_tests_fixtures
            status: na
          - task: lint_shell
            status: na
          - task: lint_typescript_declarations
            status: na
          - task: lint_typescript_tests
            status: na
          - task: lint_license_headers
            status: passed
        ---

This PR ensures that such blocks are removed.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers