Update to comply with `brainreg` v1.0.0

Update to depend on brainreg v1.0.0

Users may wish to uninstall brainreg-napari and brainreg-segment before updating. For details, see our blog post.

What's Changed

• Update to brainreg v1 compliance by @willGraham01 in #255

Full Changelog: v0.7.1...v0.8.0