5.20.3-rc1

What's Changed

• Add authentication to all docker image pulls by @ebellefontaine in #1
• [PLAT-10740] re-enable tests by @ebellefontaine in #2
• Add stale.yml by @ebellefontaine in #4
• [PLAT-10861] Add docker authentication to avoid rate-limiting by @ebellefontaine in #3
• OR5-3733: Update alpine version by @benjaminjb in #5

Full Changelog: https://github.com/objectrocket/sensu-go/commits/5.20.3-rc1