use PAT for automerge

[anthony-nhs]

Summary

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• Routine Change

Details

Use PAT for automerge

Reviews Required

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• Dev
• Test
• Tech Author
• Product Owner

Review Checklist

ℹ️ This section is to be filled in by the reviewer.

• I have reviewed the changes in this PR and they fill all or part of the acceptance criteria of the ticket, and the code is in a mergeable state.
• If there were infrastructure, operational, or build changes, I have made sure there is sufficient evidence that the changes will work.
• I have ensured the jira ticket has been updated with the github pull request link