DOCSP-40123 -- fix env var flag in example (#397)

Author: jvincent-mongodb

source/atlas-cli-deploy-docker.txt

@@ -66,7 +66,7 @@ Create a Local Atlas Deployment with Docker
 
             .. code-block:: sh
 
-               docker run -e MONGODB_INITDB_ROOT_USERNAME=user MONGODB_INITDB_ROOT_PASSWORD=pass -p 27017:27017 mongodb/mongodb-atlas-local
+               docker run -e MONGODB_INITDB_ROOT_USERNAME=user -e MONGODB_INITDB_ROOT_PASSWORD=pass -p 27017:27017 mongodb/mongodb-atlas-local
 
       The logs display as the Docker image runs.