[Bug] Environment variables do not override config file values

[nullaus]

Describe the bug or issue you're encountering Setting an environment variable to override a config file value does not work as expected. The config value is not overridden.

What are the relevant steps to reproduce, including the version(s) of the relevant software?

1. Create a .config.yaml file from the example file, leave the defaults in place.
2. Run task run-dev from the root of the repository.
3. Observe that the datum-api server will fail to connect to authz because the .config.yaml value from config-dev.example.yaml is not overridden by the environment variable set in docker/docker-compose.yml.

What is the expected behavior? The environment variable value should take precedence.