code: function runTask(taskName, directories, options, argv) {
  	return new Promise((resolve, reject) => {
  		const modulePath = tryResolve(
  			tryFile(directories, `${taskName}/index.js`),
  			`mrm-task-${taskName}`,
  			taskName
  		);
  
  		if (!modulePath) {
  			reject(new MrmUnknownTask(`Task “${taskName}” not found.`, { taskName }));
  			return;
  		}
  
  		console.log(kleur.cyan(`Running ${taskName}...`));
  
  		const module = require(modulePath);
  		Promise.resolve(module(getConfigGetter(options), argv))
  			.then(() => {
  				resolve();
  			})
  			.catch(reject);
  	});
  }
docs: Run a task.
  
  @param {string} taskName
  @param {string[]} directories
  @param {Object} options
  @param {Object} [argv]
  @returns {Promise}