Integer environment variables resolve to null

1. Newman Version: 3.9.3
2. OS details (type, version, and architecture): macOS
3. Are you using Newman as a library, or via the CLI? CLI
4. Did you encounter this recently, or has this bug always been there: It used to work once 😃

When setting an environment variable in the pre-request script:

pm.environment.set("foo", 0);

It is not sent in the request body:

{
	"x": {{foo}}
}

Steps to reproduce the problem:

1. Import the collection in Postman: https://www.getpostman.com/collections/ce1ec4ed4a3c117a7448
2. Run the tests, all is green
3. Run with newman: newman run https://www.getpostman.com/collections/ce1ec4ed4a3c117a7448
4. Test fails

Kind of similar with #1431

[kunagpal]

@MarkSonghurst @vdespa @DieGraueEminenz @BarbaraGoeller-AIT @etspaceman Could you try this with Newman v3.9.4 and confirm that it works correctly?

[kunagpal]

@MarkSonghurst Thanks for chipping in, this bug will be fixed with the next release.