v280.0.21

Updates:

• Updates nats-server from 2.10.11 to 2.10.12

What's Changed

• Remove out-of-date licenses for ruby gems by @ystros in #2498
• Remove EventMachine from nats package by @ystros in #2499
• Remove EventMachine from DNS sync scripts by @ystros in #2500
• Switch metrics server from thin to puma by @ystros in #2497
• Remove EventMachine from Health Monitor and the Director by @ystros in #2502
• Remove blobstore load test code by @aramprice in #2505

Full Changelog: v280.0.20...v280.0.21