Release checklist

[xepozz]

1. Check
   • If any collectors and proxy could be moved to the specific package Extract DebugContainerCommand to yiisoft/di #271, Extract DebugEventsCommand to yiisoft/yii-event #270
   • All collecting data are necessary (and useful) to be collected
   • All necessary collectors implement SummaryCollector interface and provide all the needed data
   • If there are memory leaks in long-running apps
   • Debugger starts, flushes data, restarts and stop well in long-running apps
2. Add docs
   • Debug lifecycle: start, data collecting, data flushing, shutdown. Also how it works with long-running apps
   • Different flow of data collecting
   • How to implement new collector and proxy for a class
   • List of all debug extensions of Yii3 packages: db, validator, aliases, yii-event, etc
   • Add what data the collectors collect to these packages
   • Mark if Timeline collector is used in a collector
3. • Increase test code coverage
4. • Static analysis max lvl Psalm 1 #267