Symfony version(s) affected: 3.4.14

Description
When using hyphen in symfony asset package name, the following error is shown:

"An exception has been thrown during the rendering of a template ("There is no "frontend-app" asset package.")."

How to reproduce

framework:
        packages:
            frontend-app:
                base_path: '/'

NOTE: in this example, when removing the hyphen or replacing hyphen with underscore, it works as expected, for example:

framework:
        packages:
            frontendapp:
                base_path: '/'

or this

framework:
        packages:
            frontend_app:
                base_path: '/'