Fixed nested Environmental Variables issue

[jakeecolution]

I also updated the version to reflect the changed and tested my new change.

Basically the issue I was having was when I went to add nested environmental variables to my .toml file.

IE:

mongo-url = "mongodb://$MONGO_USER:$MONGO_PASS@mongo:$MONGO_PORT"

I found this important because I wanted to build a configuration from multiple environmental variables for a program that accepts configuration in the toml format.

My new way allows for multiple environmental variables on one line of configuration. I used black python formatter so some of the changes are because of it.