Describe the bug

gh auth login fails with an auth required error when trying to add a new auth to a GHE instance of version < 3.0.0

gh version 1.6.0 (2021-02-17)
https://github.com/cli/cli/releases/tag/v1.6.0

Steps to reproduce the behavior

1. gh auth login
2. enter enterprise domain
3. choose to authenticate or not makes no difference
4. choose https or ssh makes no difference
5. choose paste token
6. Paste a valid token (that can be used from gh 1.2.0 and I think 1.5)
7. hit enter and fails

Expected vs actual behavior

gh auth should just work without errors, or at least have a compatibility table on the README

Logs

If you really need this, i'll reproduce again, I had cleared the terminal