chore(package): update prettier-standard to version 9.1.1

Closes #99

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "mocha": "^5.2.0",
     "mocha-junit-reporter": "^1.18.0",
     "nyc": "^12.0.2",
-    "prettier-standard": "^8.0.1",
+    "prettier-standard": "^9.1.1",
     "rimraf": "^2.6.1",
     "sinon": "^6.1.5",
     "sinon-chai": "^3.2.0",