(CLI): hotswapping should wait for Lambda's `updateFunctionCode` operation to complete

Description

Right now, when hotswapping Lambda code, we don’t wait for the updateFunctionCode API call we make to complete.

However, according to the documentation, this operation is actually eventually consistent today for Lambda functions that use Docker images, or are present in a VPC, and, even more importantly, this API will become eventually consistent for all Functions starting February 1, 2022.

We need to change our logic to wait for the operation to complete.

While implementing this, we should be cognizant of making sure we wait as effectively as possible, to not affect Lambda hotswap times too adversely. The simplest solution might be to use the standard Lambda waiter, that we use if we need to publish a new Version. Perhaps we can use a custom Waiter for this purpose, like we do for ECS service hotswapping.

Thanks a lot to @tmokmss who figured out all of this while working on Docker image Function hotswapping.

Acknowledge

• I may be able to implement this feature request
• This feature might incur a breaking change

[corymhall]

@skinny85 my comment describes the state with those changes in place. In the current state the State will always be active and the LastUpdateStatus will always be Successful.

[corymhall]

@skinny85 yep I’ve already started working on it 😃