NASA-PDS/nucleus: Nucleus v1.3.0

What's Changed

• Support for multiple data sources per PDS node (e.g. backlog and real-time under the same node) by @ramesh-maddegoda in https://github.com/NASA-PDS/nucleus/pull/223
• Track PDS product status end-to-end, verify against the live registry, and improve batch reliability at scale by @ramesh-maddegoda in https://github.com/NASA-PDS/nucleus/pull/228
• Fix race condition: serialize per-issue automation to prevent field-write collisions by @jordanpadams in https://github.com/NASA-PDS/nucleus/pull/233
• fix: remove concurrency group from issue-project-automation.yml by @jordanpadams in https://github.com/NASA-PDS/nucleus/pull/234
• Cleanup default variables by @ramesh-maddegoda in https://github.com/NASA-PDS/nucleus/pull/237

Full Changelog: https://github.com/NASA-PDS/nucleus/compare/v1.2.0...v1.3.0