fix: correctly import js-yaml to fix yaml config loading (#1033)

Author: iiroj

lib/index.js

@@ -1,7 +1,7 @@
 'use strict'
 
 const { lilconfig } = require('lilconfig')
-const { yaml } = require('js-yaml')
+const yaml = require('js-yaml')
 const debugLog = require('debug')('lint-staged')
 const stringifyObject = require('stringify-object')