ci: Update branch to sync from main

[jamesholland-uk]

Description

Update branch to sync from main, now the source READMEs are live in main

Motivation and Context

Previously the development branch was targeted

How Has This Been Tested?

Tested with GH Actions in my forked repo, see screenshot

Screenshots (if appropriate)

Checklist

• [x] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] I have added tests to cover my changes if appropriate.
• [x] All new and existing tests passed.

[jamesholland-uk]

Looks like this has since been superseded