How to force BitBucket to push a Docker image to AWS ECR after a git tag

bitbucket-pipelines.yml

#image: atlassian/default-image:2
image: python:3.7.3

pipelines:
  tags:
    'v*': # the tag is "vSomthing" like "v-0.4.2"
      - step:
         name: Build docker image and push to AWS ECR
         services:
           - docker
         caches:
           - pip
         script:
           # BitBucket > Settings > Pipelines > Repository variables =>
           #     AWS_ACCESS_KEY_ID=xxx
           #     AWS_SECRET_ACCESS_KEY=xxx
           #     AWS_REGION=xxx
           #     IMAGE_REPOSITORY=xxx.dkr.ecr.eu-central-1.amazonaws.com/repo_name # or something like that
           #     IMAGE_NAME=xxx
           - pip install awscli
           - eval $(aws ecr get-login --region $AWS_REGION --no-include-email)
           - docker build -t $IMAGE_NAME .
           - export IMAGE_ID=`docker images -q $IMAGE_NAME`
           - docker tag $IMAGE_ID $IMAGE_REPOSITORY:$BITBUCKET_TAG
           - docker push $IMAGE_REPOSITORY