CI: Fix failures on forked PRs and centralize Docker image config

[leo-amd]

Description:
This PR addresses an issue where the TransformerEngine CI workflow fails when triggered from forked repositories. GitHub Actions security policies prevent forked PRs from accessing repository variables (vars), causing the Docker image name to resolve to an empty string during docker pull.

Changes:

1. Introduced ci/ci_config.json:

   • Moves Docker image tags out of repository variables and into a version-controlled JSON file.
   • Could be used for other configurations as well.

2. Updated Select Docker Image Tag step in CI workflow:

   • Removed dependency on ${{ vars }} context.
   • Now fetches ci/docker_config.json dynamically from the upstream dev branch via curl.
   • Uses jq to parse the JSON and populate the necessary environment variables.

Benefits:

• Fixes CI for external contributors (forks).
• Centralizes configuration: Updating the Docker image in the dev branch instantly propagates the new image to all release branches (since they fetch the config dynamically), eliminating the need to cherry-pick image tag updates across multiple branches.

[matthiasdiener]

If you like, I can test this on #369 when ready.

[ipanfilo]

Here is 1 to match Jenkins logic.
Actually, desired logic is to distinct 3 situations:

• level 3 for push to any dev
• level 3 (may change independently from push to dev) for push to any monitored branch.
• level 1 for PR to any monitored branch
  but it may be further development

[matthiasdiener]

As far as I can tell, the docker image is not set correctly yet for forked PRs, even with this PR merged. See e.g. https://github.com/ROCm/TransformerEngine/actions/runs/19716553519/job/56491482864?pr=369:

BRANCH_NAME="dev"
  echo "Determining image for branch: $BRANCH_NAME"
  DEV_DOCKER_IMAGE="$DEV_IMAGE"
  REL613_DOCKER_IMAGE="$REL_IMAGE"
  IMAGE_TO_USE="$DEV_DOCKER_IMAGE"
  if [[ $BRANCH_NAME =~ ^release_v([0-9]+)\.([0-9]+)_rocm$ ]]; then
    MAJOR_VERSION=${BASH_REMATCH[1]}
    MINOR_VERSION=${BASH_REMATCH[2]}
    if (( MAJOR_VERSION == 1 )); then
      if (( MINOR_VERSION == 13 || MINOR_VERSION == 14 )); then IMAGE_TO_USE="$REL613_DOCKER_IMAGE"; fi
    fi
  fi
  echo "Selected image: $IMAGE_TO_USE"
  echo "image-tag=$IMAGE_TO_USE" >> $GITHUB_OUTPUT
  shell: /usr/bin/bash -e {0}
  env:
    DEV_IMAGE: 
    REL_IMAGE: 
Determining image for branch: dev
Selected image: 
0s
Run docker pull 
  docker pull 
  shell: /usr/bin/bash -e {0}
docker: 'docker pull' requires 1 argument

Usage:  docker pull [OPTIONS] NAME[:TAG|@DIGEST]

Run 'docker pull --help' for more information
Error: Process completed with exit code 1.

[ipanfilo]

You have to merge dev branch yaml to your fork

[matthiasdiener]

It's working now - I merged the dev branch locally, but then pushed to the wrong repo 🤦 . Sorry for the confusion.