Add Copilot setup steps to YAML documentation

[joe10832]

• I solemnly swear that this is all original content of which I am the original author
• Pull request title is prepended with [language/lang-code] (example [python/fr] for Python in French or [java] for multiple Java translations)
• Pull request touches only one file (or a set of logically related files with similar changes made)
• Content changes are aimed at intermediate to experienced programmers (this is a poor format for explaining fundamental programming concepts)
• If you've changed any part of the YAML Frontmatter, make sure it is formatted according to CONTRIBUTING.md

[joe10832]

yaml.md joe10832:patch-1

[joe10832]

yaml.md

[joe10832]

This pull request adds a new GitHub Actions job to the YAML workflow, which sets up the environment for Copilot-related steps. The new job includes checking out the repository with Git LFS support.

Workflow setup improvements:

• Added a copilot-setup-steps job to the YAML workflow in yaml.md, which checks out the repository using actions/checkout@v5 with Git LFS enabled and sets the appropriate permissions.