[docs][autoscaler] additional dependencies needs to be mentioned to build your own autoscaler image

[yxue-kabam]

What is the problem?

While building my own image for ray as described by https://github.com/ray-project/ray/blob/master/python/ray/autoscaler/kubernetes/example-full.yaml#L112 , I found additional tools needs to be added: uptime and kubernetes python package

Ray version and other system information (Python version, TensorFlow version, OS):
debian-stretch
python 3.7

Reproduction (REQUIRED)

Please provide a script that can be run to reproduce the issue. The script should have no external library dependencies (i.e., use fake or mock data / environments):
FROM debian-stretch image
apt-get install kubectl, screen, rsync

In additional, I needed to add kubernetes python package and procps debian package

If we cannot run your script, we cannot fix your issue.

• [x ] I have verified my script runs in a clean environment and reproduces the issue.
• I have verified the issue also occurs with the latest wheels.

[rkooo567]

@edoakes Seems like we should add these dependencies to our docker image?

[yxue-kabam]

@rkooo567 ray/autoscaler already have these packages if that's what you are referring to

[rkooo567]

cc @ijrsvt