Bump electron inport to ^2.0.18 for vulnerability fix (#130)

package.json

@@ -166,7 +166,7 @@
     "benchmark": "^2.1.4",
     "chai": "^4.1.2",
     "chai-http": "^4.0.0",
-    "electron": "^2.0.6",
+    "electron": "^2.0.18",
     "electron-builder": "20.22.0",
     "enzyme": "^3.3.0",
     "enzyme-adapter-react-16": "^1.1.1",

yarn.lock

@@ -3994,9 +3994,10 @@ [email protected]:
     semver "^5.5.0"
     source-map-support "^0.5.6"
 
-electron@^2.0.6:
-  version "2.0.17"
-  resolved "https://registry.yarnpkg.com/electron/-/electron-2.0.17.tgz#871c02eabcdfe11f7452c01b2f36510241b6de19"
+electron@^2.0.18:
+  version "2.0.18"
+  resolved "https://registry.yarnpkg.com/electron/-/electron-2.0.18.tgz#52f1b248c3cc013b5a870094de3b6ba5de313a0f"
+  integrity sha512-PQRHtFvLxHdJzMMIwTddUtkS+Te/fZIs+PHO+zPmTUTBE76V3Od3WRGzMQwiJHxN679licmCKhJpMyxZfDEVWQ==
   dependencies:
     "@types/node" "^8.0.24"
     electron-download "^3.0.1"