Add missing generic type for Angular 9

[bineagu]

Summary of changes:
Added the generic type in module declaration to support Angular 9.

Checklist:

• [X ] npm run build runs without error
• [X ] ng serve spawns app, Intercom messenger is visible and interactive, and there are no errors in the console

Closes issue: #101

[bineagu]

Sorry if I did something wrong, this is my first attempt at a pull request :)

[scott-wyatt]

Thanks for the PR! 🎈🎈🎈I’ll take a look at soon as I can.

[wbhob]

This looks good, except you're also going to want to upgrade @angular/* in devDependencies (so that it compiles with latest angular) and in peerDependencies (so that consumers don't get type collisions with Angular 8-). Thanks for the PR!

[egd-flaine]

Hello,
What's the status? Waiting for this merge : )
Thx