No, really, replace github with nothing at all, they are all equally off-putting, because the concept of offering (only) a user interface and in particular accounts to external parties is stupid in the first place.

Offer an email address for bug submissions.

Of course, feel free to use a bug tracker internally if you like, and possibly even with a public user interface for people who want to use it, but a user reporting a bug to your project should normally not need more than a working email client.

I have an email client that's configured to fit my needs and that allows me to efficiently process lots of emails and to write and manage outgoing messages in a single unified interface, and that's all that's really needed for most bug reports, so don't try to waste my time by forcing me to learn your user interface of choice that's not going to have the features that I want to have anyway.