Upgrade prettier to 1.7.3 (#2940)

package.json

@@ -56,7 +56,7 @@
     "jest": "21.1.0",
     "markdown-toc": "1.1.0",
     "mkdirp": "^0.5.1",
-    "prettier": "1.7.0",
+    "prettier": "1.7.3",
     "rimraf": "2.6.1",
     "rollup": "0.41.1",
     "rollup-plugin-commonjs": "7.0.0",

yarn.lock

@@ -3214,9 +3214,9 @@ preserve@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
 
-prettier@1.7.0:
-  version "1.7.0"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.7.0.tgz#47481588f41f7c90f63938feb202ac82554e7150"
+prettier@1.7.3:
+  version "1.7.3"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.7.3.tgz#8e6974725273914b1c47439959dd3d3ba53664b6"
 
 pretty-format@^21.1.0:
   version "21.1.0"