* Describe labels and container_labels correctly
* Clarify reserve_memory and limit_memory docs
* Remove default from container_labels doc
* Remove trailing whitespace
* Document min api version for configs and secrets
* Add changelog fragment
* Specify type on labels and container_labels
* Consolidate required API version descriptions
* Update reserve and limit memory docs
* Use correct power-of-two units
* Remove description about limit_memory minimum 4mb
