Bump @types/mongodb from 3.1.18 to 3.1.19

Bumps [@types/mongodb](https://github.com/DefinitelyTyped/DefinitelyTyped) from 3.1.18 to 3.1.19.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

package-lock.json

@@ -37,7 +37,7 @@
     "devDependencies": {
         "@types/express": "^4.11.1",
         "@types/google-cloud__storage": "^1.7.2",
-        "@types/mongodb": "^3.1.18",
+        "@types/mongodb": "^3.1.19",
         "@types/mongoose": "^5.3.7",
         "@types/multer": "^1.3.7",
         "apidoc": "^0.17.7",