Support for lists in environment variable overrides

[gabe-l-hart]

Is your feature request related to a problem? Please describe.

Currently, aconfig ignores lists when performing environment variable overrides. This is not ideal and should be fixed!

Describe the solution you'd like

Given a config like the following:

foo: []

You should be able to set foo with export FOO="[a,b,c]" and have "[a,b,c]" be parsed as yaml.

Describe alternatives you've considered

• You could do a simpler parsing scheme and just split on strings, but this would make typing for nested objects complex
• You could do index-based overrides for lists of objects, but this could also get quite complex to the tune of full jsonpatch or patchStrategicMerge support.