setOptionValueWithSource(key, value, source) {
    if (this._storeOptionsAsProperties) {
      this[key] = value;
    } else {
      this._optionValues[key] = value;
    }
    this._optionValueSources[key] = source;
    return this;
  }
Store option value and where the value came from.

@param {string} key
@param {object} value
@param {string} source - expected values are default/config/env/cli/implied
@return {Command} `this` command for chaining