CI: Update workflows with current templates generated by Homebrew

[PatTheMav]

Description

Updates the GitHub Actions workflows to bring them closer in line with the workflows generated by the brew tap-new command.

Motivation and Context

The workflows generated by brew tap-new are reasonably assured to be "correct" in the way they utilise the repository actions provided by Homebrew itself.

Keeping local workflows in sync with those templates reduces possibility of sudden failures.

How Has This Been Tested?

Tested on separate custom Homebrew tap.

Types of changes

• Tweak (non-breaking change to improve existing functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.