Document pattern for labeling PRs when a breaking change exists

[epage]

Building blocks

• A flag to report breaking changes
• Conditionals
  • https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#jobsjob_idstepsif
  • https://docs.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions#job-status-check-functions
• A means of applying labels
  • like https://selleo.com/til/posts/iumvmfrkhn-automate-pull-request-labels-via-github-actions