Update mmcv requirement (open-mmlab#2949)

fix docstring styles (open-mmlab#2634)

release the last version of v1.x (open-mmlab#2617)

Update version to 1.1 (open-mmlab#2144)

* update version to 1.1

* fix typo

* remove the version limit of ubelt

Bump version to 1.0.0 (open-mmlab#2029)

* bump version to 1.0.0

* fix typos

* update the version in docs

Release v1.0rc1 (open-mmlab#1805)

* update to v1.0rc1

* update maintainers

update version to v1.0rc0 (open-mmlab#1068)

Merge pull request open-mmlab#493 from hellock/master

Create a new release v0.6.0

bug fix for retinanet with 2 classes (fg/bg)

(cherry picked from commit d1cf5e5)

Merge pull request open-mmlab#310 from hellock/master

Bug fix for retinanet with 2 classes (fg/bg)