v1.1.0: Add priority field to LetterVariant schema

What's Changed

• CCM-15551: Removing Trivi by @m-houston in #51
• Maintenance: Sync latest template repo upstream by @m-houston in #52
• CCM-12869: add config -> DynamoDB publisher tooling + release-bundled GitHub Action by @m-houston in #50
• Sync upstream repository template changes and apply dependabot version updates by @m-houston in #57
• CCM-17221: Add priority field to LetterVariant schema by @m-houston in #58

Full Changelog: https://github.com/NHSDigital/nhs-notify-supplier-config/commits/v1.1.0