Workflow refactoring and improvements

[jeffhandley]

Refactor and improve the GitHub workflows.

1. Remove the step of code coverage that posts sticky comments to PRs. We might bring this back later, but we don't need it for now.
2. Only run the markdown-link-check job if markdown files are updated.
3. Allow the Build and Test workflow to be triggered manually, to run on every push to main, and to run on PRs that touch code, regardless of the target branch.
4. Declare all workflow permissions explicitly, keeping them as minimal as possible.
5. Refactor the release workflow for the 3 different package publishing jobs to run in parallel (and prevent one of them failing from preventing the others from running).
6. Pin all actions to specific SHAs, aligning with GitHub's recommended best practices.

[Copilot]

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[Copilot]

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.