Each run step gets its own shell instance, so exported variables don’t carry over. If you want that, you need to write to the GITHUB_ENV environment file, e.g.:

- name: Setup versions
  run: |
    echo "VERSION=99.99.99" >>${GITHUB_ENV}
    echo "DATE=$(date +%Y%m%d)" >>${GITHUB_ENV}

The VERSION and DATE environment variables will be available in all subsequent steps of the job.

For details, see Setting an environment variable.