Bump to v0.15.0 (open-mmlab#669)

* Bump to v0.15.0

* fixed version

unified init in 0.14.1

Bump to v0.14 (open-mmlab#580)

Bump to v0.13 (open-mmlab#529)

Bump to v0.12 (open-mmlab#455)

Bump v0.11 (open-mmlab#368)

* bump to v0.11

* update readme

Bump to v0.10 (open-mmlab#325)

* Bump to v0.10

* change version

Bump to 0.9.0 (open-mmlab#285)

* Bump to 0.9.0

* add version

Bump to v0.8 (open-mmlab#226)

* Bump to v0.8

* add version

add missing 0.7 (open-mmlab#188)