Improve language

[adammunoz]

https://github.com/basaldev/custom-service-template/blob/66fcc938921da49fe0125a2b5d087305d97e2083/index.js#L21

You can use this helper function to get the value of an environment variable or fallback value if it doesn't exist.

const MONGO_DB = utilities.getEnvironmentVariable(
  "MONGO_DB",
  "DEFAULT_MONGO_DB_CONNECTION_STRING"
);

[basal-alex]

I dunno about " an environment variable or fallback value" maybe "an environment variable with a fallback value if it doesn't exist."