Installation instructions incomplete?

[brondavies]

I've been using Serverless 1.8.0 for a few months now and I tried installing serverless-lambda-prune-plugin@1.3.0 according to the readme but sls function prune just prints

Command "prune" not found, Run "serverless help" for a list of all available commands.

Any suggestions?

[brondavies]

This might be obvious to someone with more serverless experience - I needed to add the plugin to my serverless.yml

plugins:
  - serverless-lambda-prune-plugin