Update types for MongoDB driver

package.json

@@ -47,7 +47,7 @@
     "@types/koa-router": "^7.0.42",
     "@types/koa-static": "^4.0.1",
     "@types/mithril": "^2.0.0",
-    "@types/mongodb": "^3.5.25",
+    "@types/mongodb": "^3.5.26",
     "@types/parsimmon": "^1.10.0",
     "@types/seedrandom": "^2.4.28",
     "@types/svgo": "^1.2.1",