Install fsevents as an optional dependency in package.json

package.json

@@ -120,5 +120,8 @@
     "nodemon": "^1.15.1",
     "prettier": "1.11.1",
     "webpack-dev-server": "^2.11.2"
+  },
+  "optionalDependencies": {
+    "fsevents": "^1.1.3"
   }
 }

yarn.lock

@@ -3605,7 +3605,7 @@ fs.realpath@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/fs.realpath/-/fs.realpath-1.0.0.tgz#1504ad2523158caa40db4a2787cb01411994ea4f"
-fsevents@^1.0.0:
+fsevents@^1.0.0, fsevents@^1.1.3:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/fsevents/-/fsevents-1.1.3.tgz#11f82318f5fe7bb2cd22965a108e9306208216d8"
   dependencies: