Rename package from httpauth to httpauthfirebase to follow ecosystem convention
(repo name = package name, hyphens removed). Bump httpauth dependency from
v0.1.0 to v1.0.0 and rbac indirect dependency from v0.9.0 to v1.0.0.
BREAKING CHANGE: import path unchanged (code.nochebuena.dev/go/httpauth-firebase)
but package identifier changes from httpauth to httpauthfirebase — remove any
import alias previously used to disambiguate from code.nochebuena.dev/go/httpauth.
rbac is a Tier 0 module (no micro-lib dependencies). The dependency line
incorrectly cited it as Tier 1. The module's own tier (4) is unchanged —
it remains the auth layer above the transport infrastructure.
