fix: upgrade apollo-server-express from 2.19.0 to 2.19.1

Snyk has created this PR to upgrade apollo-server-express from 2.19.0 to 2.19.1.

See this package in npm:
https://www.npmjs.com/package/apollo-server-express

See this project in Snyk:
https://app.snyk.io/org/acinader/project/8c1a9edb-c8f5-4dc1-b221-4d6030a323eb?utm_source=github&utm_medium=upgrade-pr

Author: snyk-bot