Remove outdated version specifier in docker-compose

[AetherUnbound]

We were receiving this warning when running docker commands:

$ j down
docker compose --file=docker-compose.yml --file=docker-compose.dev.yml down
WARN[0000] /home/madison/git/techbloc-airflow/docker-compose.yml: the attribute `version` is obsolete, it will be ignored, please remove it to avoid potential confusion 
WARN[0000] /home/madison/git/techbloc-airflow/docker-compose.dev.yml: the attribute `version` is obsolete, it will be ignored, please remove it to avoid potential confusion 

This prevents these errors from arising.