Update dependency prettier to v1.15.3

Author: renovate-bot

package.json

@@ -15,6 +15,6 @@
     "babel-eslint": "8.2.6",
     "eslint": "5.9.0",
     "eslint-plugin-prettier": "2.7.0",
-    "prettier": "1.14.3"
+    "prettier": "1.15.3"
   }
 }

yarn.lock

@@ -2255,9 +2255,9 @@ prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
 
-prettier@1.14.3:
-  version "1.14.3"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.14.3.tgz#90238dd4c0684b7edce5f83b0fb7328e48bd0895"
+prettier@1.15.3:
+  version "1.15.3"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.15.3.tgz#1feaac5bdd181237b54dbe65d874e02a1472786a"
 
 process-nextick-args@~2.0.0:
   version "2.0.0"