feat(core): bump core to v3.1.4

Author: mbroadst

package.json

@@ -13,7 +13,7 @@
     "official"
   ],
   "dependencies": {
-    "mongodb-core": "3.1.3",
+    "mongodb-core": "3.1.4",
     "safe-buffer": "^5.1.2"
   },
   "devDependencies": {