message: Update config to use isTruthy
diff: @@ -307,7 +307,7 @@ module.exports = function(environment) {
  shouldIncludeStyleguide: false,
  },
  'ember-cli-mirage': {
  - enabled: Boolean(MIRAGE_ENABLED),
  + enabled: isTruthy(MIRAGE_ENABLED),
  },
  'changeset-validations': {
  rawOutput: true,
  