function overwriteConfig(config, packageName, variable, value) {
    const scope = config[packageName] || (config[packageName] = {})
    scope[variable] = value
}
Overwrites a specified package config.

@param {object} config - A config object to be overwritten.
@param {string} packageName - A package name to overwrite.
@param {string} variable - A variable name to overwrite.
@param {string} value - A new value to overwrite.
@returns {void}