Fix the ws import error for typescript

[BranLiang]

Simple fix an error encountered when using apollo-server-core directly

Related issues:

#2110

TODO:

Problem could be solved with specific typescript compile configuration, and this is why no error occurs in project, but could not be used in other personal project.

"esModuleInterop": true

• Update CHANGELOG.md with your change (include reference to issue & this PR)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass

[apollo-cla]

@BranLiang: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Meteor Contributor Agreement here: https://contribute.meteor.com/

[abernix]

Thanks for opening this, but this should already be fixed thanks to #2230, and specifically, c1607cb. That fix should be included in Apollo Server 2.4.3. Please test and feel free to ping back if it doesn't solve it for you.

Thanks again!