Update commander to the latest version 🚀 (#13)

* fix(package): update commander to version 2.20.0

* chore(package): update lockfile yarn.lock

Author: greenkeeper[bot]

package.json

@@ -13,7 +13,7 @@
   "dependencies": {
     "bunyan": "^1.8.12",
     "bunyan-format": "^0.2.1",
-    "commander": "2.19.0",
+    "commander": "2.20.0",
     "css-tree": "1.0.0-alpha25",
     "dotenv": "^7.0.0",
     "puppeteer": "^1.12.2",

yarn.lock

@@ -895,7 +895,12 @@ combined-stream@^1.0.6, combined-stream@~1.0.6:
   dependencies:
     delayed-stream "~1.0.0"
 
-commander@2.19.0, commander@~2.19.0:
+commander@2.20.0:
+  version "2.20.0"
+  resolved "https://registry.yarnpkg.com/commander/-/commander-2.20.0.tgz#d58bb2b5c1ee8f87b0d340027e9e94e222c5a422"
+  integrity sha512-7j2y+40w61zy6YC2iRNpUe/NwhNyoXrYpHMrSunaMG64nRnaf96zO/KMQR4OyN/UnE5KLyEBnKHd4aG3rskjpQ==
+
+commander@~2.19.0:
   version "2.19.0"
   resolved "https://registry.yarnpkg.com/commander/-/commander-2.19.0.tgz#f6198aa84e5b83c46054b94ddedbfed5ee9ff12a"
   integrity sha512-6tvAOO+D6OENvRAh524Dh9jcfKTYDQAqvqezbCW82xj5X0pSrcpxtvRKHLG0yBY6SD7PSDrJaj+0AiOcKVd1Xg==