fix(package): update react-dom to version 16.5.2

Closes #10

Author: greenkeeper[bot]

package.json

@@ -23,7 +23,7 @@
     "react-bootstrap": "^0.31.2",
     "react-codemirror": "^1.0.0",
     "react-datetime": "^2.9.0",
-    "react-dom": "^15.6.1",
+    "react-dom": "^16.5.2",
     "react-fontawesome": "^1.5.0",
     "react-ga": "^2.1.2",
     "react-google-maps": "^8.0.0",