Release Procedure

1. review requirements.txt, update pins as needed
2. bump downloader docker image versions in default.cfg, including occasional rebuild of miniwdl_tools
3. manual macOS testing: make unit_tests
4. git tag -a vX.Y.Z on main branch
5. push to GitHub & await CI success
6. fast-forward release and vX.Y branches to the vX.Y.Z tag; push them to GitHub.
7. release to PyPI: make pypi
8. create & groom GitHub Release
9. conda: merge the automatic PR opened on miniwdl-feedstock, updating dependency versions as needed; double-check the conda-forge build succeeds after merging.
10. double-check documentation auto-updated, or otherwise troubleshoot Read the Docs build
11. smoke tests:

    docker run --rm -it -v /var/run/docker.sock:/var/run/docker.sock -v /tmp:/tmp ubuntu:18.04 \
      bash -c 'apt-get -qq update && apt-get install -y python3-pip && pip3 install miniwdl && miniwdl run_self_test'
    
    docker run --rm -it -v /var/run/docker.sock:/var/run/docker.sock -v /tmp:/tmp continuumio/miniconda3 \
      bash -c 'conda install -y -c conda-forge miniwdl && miniwdl run_self_test'