2.12.28

What's Changed

• [kubernetes][jobsets] dont set replicas to 0 by @valayDave in #2118
• Refactor system event logger and monitor, add new metrics by @talsperre in #2065
• prepare release 2.12.28 by @darinyu in #2125
• ping r version to 4.4.1 to fix test by @wangchy27 in #2127

Full Changelog: 2.12.27...2.12.28