Brief description of your issue

Getting ready to release a package to winget, there is no way to provide Authorization and Accept headers to WinGetCreate's commands, such as "new".
I'm getting ready to release an app, but its on my private github. I have a PAT, and with proper auth I want to be able to get ready to release the app, generating the manifest from the new command.
It can be a simple parameter provided as environment variables to the internal HttpClietn from PackageParser.

Steps to reproduce

wingetcreate new
Provide url to private github release.

Expected behavior

Given proper environment variable setup, I can generate a manifest by pointing to a URL that requires auth.

Actual behavior

Fails with 404.

Environment

v1.10.3.0