SDK-1064: Make recommendation to use .env file with Docker examples more explicit

Author: emmas-yoti

README.md

@@ -235,7 +235,7 @@ To run the Flask or Django container:
    * `cd examples/yoti_example_flask` for __Flask__   
    __OR__
    * `cd examples/yoti_example_django` for __Django__
-1. Make sure the environment variables `YOTI_SCENARIO_ID`, `YOTI_CLIENT_SDK_ID` and `YOTI_KEY_FILE_PATH` are set (instructions in the [Configuration](#configuration) section). _Please note that with Docker, the .pem file must reside in a location within where docker is being run from, so it should be placed somewhere under the respective  [yoti_example_flask](/examples/yoti_example_flask)/[yoti_example_django](/examples/yoti_example_django) folders._
+1. Make sure the environment variables `YOTI_SCENARIO_ID`, `YOTI_CLIENT_SDK_ID` and `YOTI_KEY_FILE_PATH` are set using an .env file (instructions in the [Configuration](#configuration) section). _Please note that with Docker, the .pem file must reside in a location within where docker is being run from, so it should be placed somewhere under the respective  [yoti_example_flask](/examples/yoti_example_flask)/[yoti_example_django](/examples/yoti_example_django) folders._
 1. Rebuild the images if you have modified the docker-compose.yml file with
    - `docker-compose build --no-cache`
 1. Start the container with `docker-compose up`