Option to not do docker pull?

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If you have a feature request that is relevant to this repository, the runner, then please include the information below:

Describe the enhancement
If I have a local runner and a locally maintained docker image i.e. not stored on a repository, I would like to avoid the "docker pull" step, which then fails.

Code Snippet

name: Self Hosted Tests

on: [push]

jobs:
  integration_tests:
      runs-on: self-hosted
      container:
          image: python3.6:latest
      steps:
      - name: Checkout
        uses: actions/checkout@v2
      - name: What java version do we have
        run: java -version

Additional information
The image python3.6:latest is in my self-hosted runner's docker images. It doesn't exist in DockerHub or any other repository, and I don't want it to, because it should only ever be run on my self-hosted runner.

NOTE: if the feature request has been agreed upon then the assignee will create an ADR. See docs/adrs/README.md

Start with the self-hosted runner's container-job handling and reproduce the workflow shown in the issue using a locally available image that is absent from Docker Hub. The work is done when an explicit option allows the job to use that local image without attempting docker pull, while normal image behavior remains unchanged; review docs/adrs/README.md for the repository's ADR process.