Build failing with typescript next

[ahardin13]

Builds with npm run build and CI are failing.
https://travis-ci.org/microsoft/TSJS-lib-generator/builds/535138688?utm_source=github_status&utm_medium=notification

After changing typescript to 3.4.4 in package.json and doing an npm i, npm run build succeeds.

[saschanaz]

Fixed by #703

[saschanaz]

@github-actions close

[github-actions]

Closing because @saschanaz is one of the code-owners of this repository.