1.9.0

:rocket: (Enhancement)

• feat(metrics): added synchronous gauge #4528 @clintonb
• feat(api): allow adding span links after span creation #4536 @seemk
  • This change is non-breaking for end-users, but breaking for Trace SDK implmentations in accordance with the specification as new features need to be implemented.
• feat: support node 22 #4666 @dyladan