How to make an azure devops pipeline check that a feature branch is update to date with develop?

How about this, to check for merge base difference:

steps:
- script: |
    git fetch origin develop
    BASE=$(git merge-base HEAD origin/develop)
    if [ "$BASE" != "$(git rev-parse origin/develop)" ]; then
      echo "Your branch is not up-to-date with develop."
      exit 1
    else
      echo "Branch is up-to-date with develop."
    fi
  displayName: 'Check if branch is up-to-date with develop'