make standard a dev dependency

Author: philschatz

package.json

@@ -15,8 +15,7 @@
     "dotenv": "^6.2.0",
     "puppeteer": "^1.12.2",
     "sizzle": "2.3.3",
-    "source-map": "0.7.3",
-    "standard": "^12.0.1"
+    "source-map": "0.7.3"
   },
   "bin": {
     "css-coverage": "bin/css-coverage.js"
@@ -33,6 +32,7 @@
   "author": "Philip Schatz <phil@cnx.org>",
   "license": "MIT",
   "devDependencies": {
-    "sass": "^1.17.0"
+    "sass": "^1.17.0",
+    "standard": "^12.0.1"
   }
 }