fix(package): update chalk to version 4.0.0

Closes #26

Author: greenkeeper[bot]

package.json

@@ -20,7 +20,7 @@
   },
   "main": "lib/index.js",
   "dependencies": {
-    "chalk": "^2.0.0",
+    "chalk": "^4.0.0",
     "figures": "^2.0.0",
     "highlight-es": "^1.0.0",
     "lodash": "^4.15.0",