Rename default branch

[kfcampbell]

This changes the default branch from master --> main in our workflows and docs to match the current state of the repo.

---

Behavior

Before the change?

• Links and Actions used the "master" default branch name.

After the change?

• Links and Actions use the "main" default branch name

Additional info

Pull request checklist

• [ ] Tests for the changes have been added (for bug fixes / features)
• [X] Docs have been reviewed and added / updated if needed (for bug fixes / features)
• [X] Added the appropriate label for the given change

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• [ ] Yes (Please add the Type: Breaking change label)
• [X] No

If Yes, what's the impact:

• N/A

Pull request type

Please add the corresponding label for change this PR introduces: - Bugfix: `Type: Bug` - Feature/model/API additions: `Type: Feature` - Updates to docs or samples: `Type: Documentation` - Dependencies/code cleanup: `Type: Maintenance` ----