Fix breaking version change in aws-cli during circleci pipeline

[bmonkman]

Version 1.19.45 of aws-cli introduced a breaking change that won't work with Python 2.7, which is what the exectuor was using for the build_and_push step. This will require the following changes:

Bump the aws-cli orb to version 2.0.0:

orbs:
  aws-cli: circleci/aws-cli@2.0.0

Change the executor for the build_and_push job to use python 3:

  build_and_push:
    executor: aws-eks/python3

Add a new first step to the build_and_push job to enable using docker from within a docker container during the build:

    steps:
      - setup_remote_docker:
          docker_layer_caching: true