Docker Plugin - When updating environment variables, not able to have an "=" in the variable

Docker Plugin - When updating environment variables, not able to have an "=" in the variable​

Plesk Onyx on Ubuntu 18.0.4​

I have a few docker container that are running asp.net core services. A few of the services connect to a database. I need to be able to manage the database in an environment variable. Currently I have to SSH into the container...​